DEPARTMENT  OF  THE  INTERIOR  ' 

John  Barton  Payne,  Secretary 


United  States  Geological  Survey 
George  Otis  Smith,  Director 


THE 

PREPARATION  OF  ILLUSTRATIONS 


FOR  REPORTS  OF  THE 


Vmm^  STATES  GEOLOGICAL  SURVEY 


WITH  BRIEF  DESCRIPTIONS  OF  PROCESSES 
OF  REPRODUCTION 


BY 

JOHN  L.  RIDGWAY 


WASHINGTON 

GOVERNMENT    PRINTING    OFFICE 
1920 


DEPARTMENT  OF  THE  INTERIOR 

John  Barton  Payne,  Secretary 


United  States  Geological  Survey 

George  Otis  Smith,  Director 


THE 


PREPARATION  OF  ILLUSTRATIONS 


FOE,   REPORTS    OF   THE 


DMTED  STATES  GEOLOGICAL  SURTEY 


WITH  BRIEF  DESCRIPTIONS  OF  PROCESSES 
OF  REPRODUCTION 


BY 


JOHN  L.  RIDGWAY 


WASHINGTON 

GOVERNMENT    PRINTING    OFFICE 
1920 


For  sale  by  the  Superintendent  of  Documents,  U.  S.  Government  Printing  Office 
Washington  25,  D.  C.     -     Price  65  cents 


THE  PREPARATION  OF  ILLUSTRATIONS 

FOR  REPORTS  OF  THE 

UNITED  STATES  GEOLOGICAL  SURVEY 

BY 
JOHN  L.  RIDGWAY 


.jHgee^'-EN'^^'^ 


CONTENTS. 


Past  I.  Preparation  by  Authors. 

[Pag«. 

Introduction 7 

Pui*pose  and  value  of  illustrations 8- 

Selection  and  approval  of  illustrations 8 

Submittal  of  illustrations 10 

Kinds  of  illustrations 10 

Sizes  of  illustrations 11 

Subdivisions  of  plates  and  figures 12 

Preparation  of  copy  by  authors 12 

Character  of  original  material 12 

Preliminary  preparation  of  maps 13 

Material  available  for  base  maps 14 

Basic  features  of  maps 17 

Standard  scales 18 

Orientation  of  maps 18 

Projection 18 

Explanation , 19 

Titles  of  maps  and  other  illustrations 19 

Symbols  used  on  maps 20 

General  features 20 

Letter  symbols 20 

Oil  and  gas  symbols 21 

Symbols  for  use  on  maps  showing  features  of  ground  water 21 

Black-line  conventions 23 

Materials  used  in  preparing  maps 23 

Paper 23 

Bristol    board 24 

Tracing  linen 24 

Inks 25 

Drawing  pens 2.5 

Pencils 25 

Rubber  erasers  and  cleaners 25 

Colored  pencils  and  crayons 26 

Water  colors 26- 

Japanese  transparent  water  colors 26- 

Coloring  geologic  maps 27 

Diagrams 28; 

Essential  features 28 

Plans  of  mine  workings 29 

Sections 29 

Lithologic  symbols 32 

Use  of  photographs  as  illustrations 32 

Essential  features 32 

Copyrighted   photographs 33 

3 


4  CONTENTS. 

Preparation  of  copy  by  authors — Continued. 

Use  of  photographs  as  illustrations — Continued.  Page. 

Sources  of  photographs 34 

Lending  original  photographs  and  dramngs 34 

Unpublished  photographs 34 

Specimens 34 

General  requirements 34 

Borrowed  and  fragile  specimens 35 

Transmittal  of  paleontologic  specimens 35 

Making  up  plates ^__  36 

Reuse  of  illustrations 37 

Approval  of  finished  illustrations 38 

Revision  of  illustrations 38 

Submittal  of  proofs 38 

Proof-reading  illustrations 39 

General    considerations 39' 

Pabt  II.  Prepakation  by  Draftsmen. 

General  directions 41 

Instruments 42 

Classification  of  material 42 

Preparation  of  maps 43 

Projection 43 

Details  of  base  maps 45 

Transferring  or  copying 46 

Tracing 46 

Celluloid  transferring 47 

Sketching  by  reticulation 47 

The  "shadowless  drafting  table" 47 

Topographic  features 48 

Relief 48 

Hydrography 51 

Cultural  features 52 

Lettering 53 

General  directions 53 

Lettering  by  type 54 

Abbreviations 55 

Names  of  railroads 57 

IMake-up  of  maps 57 

Forms  for  certain  features 57 

Border 57 

Title 58 

Explanation 58 

Graphic  scales  for  maps 59 

Symbols 61 

Areal  patterns  for  black  and  white  maps CI 

Standard  colors  for  geologic  maps 63 

Reduction  or  enlargement  of  maps 63 

Diagrams 64 

Sections .     64 

Plans  and  cross  sections  of  mines G5 


COXTENTS.  O 

Page. 

Drawings  of  specimens  of  rocljs  and  fossils 66 

Methods,  used 66 

Brush  and  pencil  drawings 66 

Pen  drawings 67 

Ketouching  photographs  of  specimens 68 

Landscape  drawings  from  poor  photographs 68 

Pen  drawings  made  over  photographs ^ 68 

Brush  drawings  from  poor  photographs 69 

Outdoor  sketches 69 

Drawings  of  crystals 70 

Retouching  photographs 70 

Part  III.  Peocesses  of  Repboducing  Illustkatioxs. 

Methods  employed 72 

Photoengraving 72 

General  features 72 

Zinc  etching 73 

Copper  etching  in  relief 75 

Half-tone   engraving 75 

Three-color  half-tone  process 78 

Wax  engraving  (the  cerotype  process) 80 

Wood  engraving 81 

Photogelatin  processes 82 

Lithography ^ 83 

Original  process 83 

Photolithography 86 

Offset  printing 87 

Chromolithography 87 

Engraving  on  stone  and  on  copper 89 

Appendix. 

Length  of  degrees  of  latitude  and  longitude 91 

Metric  system  and  equivalents 92 

Geologic  eras,  periods,  systems,  epochs,  and  series 92 

Chemical  elements  and  symbols 93 

Greek  alphabet 93 

Roman  numerals 93 

Mathematical   signs- 94 

Names  of  rocks = 94 


ILLUSTRATIONS. 


Page. 

Plate  I.  Methods  of  inserting  plates  and  figures 10 

II.  Symbols  used  on  geologic  maps,  economic  maps,  and  mine  plans 20 

III.  Lithologlc  symbols  used  in  structure  and  columnar  sections  to 

represent  different  Ifinds  of  rock 32 

IV.  Symbols  used  on  base  maps 52 

V.  Reduction  sheet  used  in  lettering  illustrations 54 

VI.  Half-tone  prints  showing  effects  produced  by  the  use  of  six 

standard   screens 56 

VII.  Details  of  the  make-up  of  a  geologic  map 58 

VIII.  Patterns  used  to  show  distinctions  between  areas  on  black  and 

white  maps 60 

IX.  Diagrams  and  curves 64 

Figure  1.  Diagrams  showing  principal,  guide,  and  auxiliary  meridians, 
standard  and  special  parallels  and  correction  lines,  and  sys- 
tem of  numbering  townships,  ranges,  and  sections 16 

2.  Conventional  lines  used  in  preparing  plans  and  diagrams  of 

mine  workings  to  distinguish  different  levels 39 

3.  Section   and   perspective   view   showing   relations  of  surface 

features  to  the  different  kinds  of  rocks  and  the  structure 

of  the  beds 30 

4.  Sections  of  coal  beds 31 

5.  Diagram  illustrating  method  of  projecting  a  map 44 

6.  Methods  of  expressing  relief  by  contour  lines,  by  hachures,  by 

shading  on  stipple  board,  and  by  a  brush  drawing 491 

7.  Designs  for  bar  scales 60| 

8.  Method  of  making  a  bar  scale  for  a  map  of  unknown  scale 60j 

0.  Map  bearing  six  areal  line  patterns 62/ 

10.  Diagram  showing  method  of  marking  maps  for  reduction  or  en- 

largement  (for  record) 6^ 

11.  Structure  section  showing  method  of  determining  the  succession 

of  folds 6{| 

6 


THE  PEEPARATION  OF  ILLUSTKATI0N8  FOR  REPORTS  OF 
THE  UNITED  STATES  GEOLOGICAL  SURVEY. 


By  John  L.  Ridgway. 


PART  I.    PREPARATION  BY  AUTHORS. 

INTRODUCTION. 

There  has  been  an  obvious  need  in  the  Geological  Survey  of  a  paper 
devoted  wholly  to  illustrations.  No  complete  paper  on  the  character, 
use,  and  mode  of  preparation  of  illustrations  has  been  published  by 
the  Survey,  though  brief  suggestions  concerning  certain  features  of 
their  use  have  been  printed  in  connection  with  other  suggestions  per- 
taining to  publications.  The  present  paper  includes  matter  which 
it  is  hoped  will  be  of  service  to  authors  in  their  work  of  making  up 
original  drafts  of  illustrations  and  to  draftsmen  who  are  using  these 
originals  in  preparing  more  finished  drawings,  but  it  is  not  a  technical 
treatise  on  drafting. 

The  effectiveness  of  illustrations  does  not  depend  entirely  on  good 
drawings  nor  on  good  reproduction ;  it  may  be  due  in  large  part  to 
the  inherent  character  of  the  rough  material  submitted.  If  this 
material  is  effective  or  striking  the  finished  illustrations,  if  well  made, 
will  be  equally  effective  and  striking.  Each  step  in  the  making  of  an 
illustration — first  the  preparation  of  the  author's  original  or  rough 
draft,  next  the  final  drawing,  and  last  the  reproduction — is  closely 
related  to  the  others,  and  each  is  dependent  on  the  others  for  good 
results.  If  the  material  has  been  well  handled  at  all  three  steps  the 
resulting  illustration  should  be  above  criticism ;  if  it  has  been  poorly 
handled  at  any  one  of  the  three  the  effectiveness  of  the  illustration 
is  either  impaired  or  ruined. 

A  consideration  of  processes  of  reproduction  is  essential  in  the 
preparation  of  all  illustrations,  and  the  influence  or  effect  of  the 
process  to  be  selected  on  the  methods  of  preparing  a  drawing  has 
seemed  to  warrant  the  presentation  of  brief  descriptions  of  the  proc- 
esses usually  employed  by  the  Geological  Survey.  These  descrip- 
tions include  statements  as  to  the  kind  of  copy  that  is  suitable  for 
each  process,  the  result  produced  by  each,  and  the  relative  cost  of 
the  processes. 

7 


8  PREPARATION  OF  ILLUSTRATIONS. 

PURPOSE   AND    VALUE    OF   ILLUSTRATIONS. 

An  illustration  in  a  report  of  the  Geological  Surve}^  is  not  merely 
a  picture  having  a  remote  bearing  on  the  subject  matter  of  the  re- 
port; it  must  represent  or  explain  something  discussed  or  mentioned 
in  order  to  become  an  illustration  in  the  true  sense  of  the  term.  The 
illustrations  used  in  the  Survej^'s  reports  are  not  employed  for  em- 
bellishment ;  the  more  pictorial  kinds  may  be  in  some  measure  decora- 
tive, but  decoration  is  distinctly  not  their  primary  purpose.  The 
illustrations  used  in  popular  literature  are  designed  to  meet  a  public 
demand  for  ornament  or  attractiveness.  Those  used  in  scientific 
publications  should  be  made  plain  and  direct,  without  attempt  to 
ornament  or  beautify.  In  the  literature  of  science  illustrations  made 
by  the  reproduction  of  photographs  or  of  explanatory  diagrams  or 
maps  are  intended  simply  to  furnish  greater  illumination,  and  if  the 
illustrations  display  photographic  reality  most  statements  or  con- 
clusions thus  illuminated  seem  less  open  to  dispute.  A  photograph 
may  thus  serve  the  double  purpose  of  explanation  and  corrobora- 
tion. The  graphic  expression  of  data  and  of  details  in  a  Survey  report 
is  intended  to  aid  the  reader  in  comprehending  the  report,  and  this 
is  the  prime  advantage  of  its  use,  but  it  also  enables  the  writer 
to  omit  from  his  text  numerous  descriptive  details.  It  would  gen- 
erally be  difficult  without  illustrations  to  present  a  clear  picture  of 
the  geology  of  a  region  in  its  exact  relations,  and  especially  to  de- 
scribe adequately  the  form  and  the  details  of  the  structure  of  many 
fossils.  The  tasks  of  both  the  writer  and  the  reader  of  reports  on 
geology  and  kindred  subjects  are  thus  greatly  facilitated  by  geologic 
maps,  sections,  paleontologic  drawings,  and  illustrations  of  other 
kinds. 

The  responsibility  for  good  and  effective  illustrations  rests  largely 
upon  the  author,  who  should  select  and  plan  his  illustrations  with 
a  view  to  their  utility  in  aiding  the  reader  to  understand  his 
report. 

SELECTION    AND   APPROVAL   OF   ILLUSTRATIONS. 

There  is  no  rule  limiting  the  number  of  illustrations  that  may  be 
used  in  a  publication  of  the  Geological  Survey,  but  in  selecting  illus- 
trations for  a  report  an  author  may  easily  fall  into  the  error  of  over- 
illustration.  The  number  of  diagi-ammatic  drawings  or  of  drawings 
that  express  the  author's  deductions  is  rarely  in  excess  of  the  needs 
of  a  paper,  but  the  number  of  photographs  submitted  is  often  exces- 
sive. The  number  of  images  in  a  manuscript  may  be  a  factor  in 
determining  the  proper  number  of  illustrations,  but  as  the  need  of 
illustrations  varies  greatly  from  paper  to  paper  this  factor  alone  is 


PREPAKATIOl^   OF  ILLUSTRATIOH^S.  9 

not  decisive.    The  tendency  to  overillustrate  led  the  Director  to  issue 
the  following  order '  governing  the  approval  of  illustrations : 

The  primary  responsibility  for  the  selection  of  illustrative  material  shall  rest 
upon  the  author  and  the  chief  of  the  branch  transmitting  the  report.  No  one 
knows  the  subject  matter '  of  the  report  better  than  its  author,  though  a 
sympathetic  critic  is  usually  needed  to  correct  the  personal  equation  that  may 
express  itself  in  an  excessive  number  of  illustrations  or  the  use  of  photographs 
into  which  no  one  but  the  field  man  himself  can  read  what  he  wishes  to  illus-; 
trate.  The  approval  by  the  chief  of  branch  of  the  illustrations  selected  by  the 
author  will  be  taken  as  vouching  for  those  illustrations  as  essential  and  ade-i 
quate,  and  the  scientific  value  of  the  illustrations  will  not  be  subject  to  review 
in  the  section  of  illustrations. 

The  chief  of  the  section  of  illustrations  shall  decide  the  technical  questions 
relating  to  the  preparation  of  these  illustrations  for  reproduction  and  may 
recommend  the  rejection  of  any  that  do  not  promise  effective  or  economical 
reproduction.  In  the  consideration  of  such  questions,  especially  any  relating 
to  maps,  the  cooperation  of  the  editor  of  geologic  maps  and  chief  engraver  will 
be  expected. 

The  judgment  of  an  author  as  to  the  illustrative  A'alue  of  a  photo- 
graph is  likely  to  be  biased  by  his  knowledge  of  the  features  that  are 
actually  included  in  the  view  represented,  not  all  of  which  may  be 
shown  clearly  in  the  photograph ;  his  knowledge  of  all  the  features 
enables  him  to  see  more  in  his  picture  than  his  readers  will  be  able 
to  recognize  without  detailed  description.  Photographs  in  which 
special  or  significant  features  are  obscured  by  foliage  or  lost  in  hazy 
distance  do  not  make  acceptable  illustrations,  and  the  use  of  a 
picture  that  requires  much  description  to  make  it  illustrate  reverses, 
in  a  measure,  the  relations  of  text  and  illustrations. 

A  photograph  is  not  necessarily  good  for  reproduction  simply  be- 
cause it  shows  some  particular  feature  to  be  illustrated;  the  quality 
of  the  print  it  will  afford  when  reproduced  from  an  engraved  plate 
should  also  be  considered.  Some  loss  of  detail  by  reproduction  must 
be  expected,  and  therefore  only  the  clearest  and  most  effective  prints 
obtainable  should  be  submitted. 

If  an  author  has  difficulty  in  making  his  preliminary  or  "  original  " 
drawings  he  may  request  that  a  draftsman  be  detailed  to  aid  him. 
The  request  should  be  made  to  the  Director  through  the  chief  of 
branch  and  properly  approved.  The  work  will  then  be  done  in  the 
section  of  illustrations  as  advance  preparation,  but  finished  drawings 
should  not  be  thus  prepared  unless  the  conditions  are  unusual.  The 
administrative  geologist  reviews  all  illustrations  submitted  and  rep^ 
resents  the  Director  in  matters  relating  to  illustrations. 


^From   Survey  Order  63,   Oct.   20,   1915. 


10  PREPARATION   OF   ILLUSTRATIONS. 

SUBMITTAL   OF   ILLUSTRATIONS. 

All  material  intended  for  illustrations,  except  paleontologic  speci- 
mens, should  be  submitted  with  the  manuscript  of  the  paper  to  be 
illustrated  but  in  a  separate  package  marked  "  Illustrations  to  ac- 
company a  paper  on by ."    The  package  should  contain  a 

carbon  copj'  of  the  list  of  illustrations  that  accompanies  the  manu- 
script or,  if  the  titles  to  be  printed  on  or  with  the  illustrations  in- 
clude fuller  descriptions  than  are  given  in  that  list,  a  carbon  copy  of 
the  list  giving  complete  titles  and  descriptions,  the  original  of  which 
should  also  accompany  the  manuscript.  In  the  list  each  plate 
and  figure  should  be  separately  numbered  consecutively  in  the  order 
in  which  it  should  appear  in  the  report,  and  a  figure  opposite  each 
title  should  show  the  number  of  the  manuscript  page  on  which  the 
illustration  is  first  mentioned  or  most  fully  discussed.  Roman  nu- 
merals should  be  used  for  the  plates  and  arabic  numerals  for  the  fig- 
ures. Each  drawing  or  photograph  should  bear,  in  addition  to  the 
number  and  title,  any  suggestions  concerning  preparation,  reduction, 
and  method  of  reproduction  which  the  author  may  consider  especially 
desirable.    The  list  should  be  headed  "  Illustrations." 

Specimens  other  than  fossils  that  are  to  be  illustrated  must  be  sub- 
mitted directly  to  the  section  of  illustrations,  but  the  author  may 
first  obtain  photographic  prints  of  them  in  order  to  make  up  his  plates. 
The  specimens  should  be  carefully  packed  and  any  that  are  fragile 
should  be  so  marked. 

KINDS    OF   ILLUSTRATIONS. 

The  illustrations  in  reports  of  the  Geological  Survey  may  be  classi- 
fied into  five  more  or  less  distinct  groups — (1)  maps,  (2)  diagrams 
(including  graphs,  sections,  plans,  figures  of  apparatus,  and  stereo- 
grams), (3)  outdoor  photographs,  (4)  photographs  and  drawings  of 
specimens,  and  (5)  sketches.  These  may  be  further  divided  into  two 
large  groups,  which  may  be  called  permanent  and  ephemeral.  The 
permanent  group  includes  illustrations  that  do  not  lose  value  through 
lapse  of  time  or  by  natural  alteration,  such  as  detailed  geologic  maps, 
well-prepared  structure  sections,  views  of  specimens,  and  good  photo- 
graphs or  draw^ings  of  natural  phenomena ;  the  ephemeral  group  in- 
cludes maps  showing  progress,  key  maps,  diagrams  showing  yearly 
production,  and  many  others  that  should  be  prepared  in  such  a  way 
as  to  minimize  cost  of  preparation  and  reproduction. 

The  illustrations  will  be  finally  divided  into  plates  and  figures 
when  they  are  fully  prepared,  but  if  an  author  desires  to  determine 
the  classification  in  advance  of  ti-ansmittal  he  should  submit  his 
material  to  the  section  of  illustrations,  where  methods,  processes,  and 
reductions  will  be  decided  for  each.     In  determining  which  shall  be 


U.  S.  GEOLOGICAL  SURVEY 


PREPARATION  OF  ILLUSTRATIONS     PLATE  I 


METHODS  OF  INSERTING  PLATES  AND  FIGURES. 
1,  2,  3,  5,  6,  7,  plates;  4,  8,  9,  10,  figures;  11,  pocket. 


PREPARATION  OF  ILLUSTRATIONS.  11 

plates  and  which  shall  be  figures,  size  and  method  of  reproduction  are 
the  only  factors  to  be  considered ;  there  are  no  other  real  differences. 
Illustrations  that  require  separate  or  special  printing,  such  as  those 
reproduced  by  lithography  and  by  the  photogi-avure,  photogelatin, 
and  three-color  processes,  must  be  printed  separately  from  the  text  as 
plates  and  inserted  in  the  report  at  the  proper  places ;  those  that  are 
reproduced  by  relief  processes,  such  as  zinc  and  copper  etching  and 
wax  engraving,  if  not  too  large,  can  be  printed  with  the  text  as 
figures.  If  an  illustration  to  be  reproduced  by  a  relief  process  is 
marked  for  reduction  to  a  size  not  exceeding  that  of  the  page  of  the 
text,  it  can  be  called  a  figure  and  be  printed  with  the  text.  Half 
tones,  though  etched  in  relief,  are  rarely  made  text  figures  in  Survey 
reports,  because  to  give  satisfactory  impressions  they  must  be  printed 
on  the  best  quality  of  coated  paper,  which  is  not  used  for  the  text. 
By  using  the  coarser  screens  shown  in  Plate  VI  (p.  56),  however,  a 
half-tone  cut  may  be  made  that  can  be  used  in  the  text  if  it  is  smaller 
than  the  page. 

SIZES    OF   ILLUSTRATIONS. 

The  regular  book  publications  of  the  Geological  Survey  are  issued 
in  three  sizes — (1)  octavo  (annual  reports  of  the  Director,  statistical 
reports  on  mineral  resources,  bulletins,  and  water-supply  papers)  ; 
(2)  quarto  (professional  papers  and  monographs)  ;  (3)  folio  (geo- 
logic folios).  The  following  table  gives  the  measure  of  the  text  of 
each  size  and  the  measure  of  the  trimmed  page,  in  inches : 

Size  of  text.  Size  of  page. 

Octavo.- _ 41     by  7^  H  by    9i 

Quarto 7^  by  9H  9J  by  llf 

Folio ISM  by  175  18i  by  2U 

Most  professional  papers  are  printed  in  two  columns  of  type,  each 

3  inches  wide,  and  folios  are  printed  in  three  columns,  each  4f  inches 
wide.  A  text  figure  in  one  of  these  publications  can  be  made  to  fit  one 
or  more  columns,  and  it  may  run  the  full  length  of  the  text  page. 

The  limits  of  the  dimensions  of  plates  and  figures,  in  inches,  are 
given  in  the  following  table.  If  for  any  reason  a  plate  can  not  be 
reduced  to  the  dimensions  of  a  page  it  can  be  folded  once  or  more; 
and  if  it  is  large  and  unwieldy  it  may  be  placed  in  a  pocket  on  the 
inside  of  the  back  cover.     (See  PI.  I.) 

Single-  Plate  with 

page  plate.  one  side  fold.  Text  figure. 

Octavo 4|  by     7^        7^  by    8^  4|  by     7^ 

Quarto-. 7     by     9^         9^  by  14f         3^  or     7       by     9^ 

Folio 15     by  17i         41  or  13i|  by  17i 

For  an  octavo  report  a  single-page  plate  with  side  title  should  be 

4  inches  or  less  in  width,  and  a  plate  with  bottom  title  should  be  7 
inches  or  less  in  depth.    In  other  words,  the  actual  depth  and  width 


12  PREPARATION"  OF  ILLUSTRATIONS. 

of  a  single-page  plate  in  a  page  of  any  size  must  depend  on  the  num- 
ber of  lines  in  its  title,  the  inclusion  of  which  should  not  extend 
the  matter  much,  if  any,  beyond  the  dimensions  given  in  the  table. 
A  difference  of  1  inch  or  less  in  the  width  of  a  folding  plate  may 
determine  whether  it  must  be  folded  once  or  twice,  so  that  by  con- 
sulting this  table  an  author  may  save  expense  in  binding  and  promote 
the  reader's  convenience  in  handling  the  plate. 

A  text  figure  (including  the  title)  can  not  extend  beyond  the  text 
measure  but  may  be  of  an}^  size  or  shape  within  that  measure,  as 
shown  on  Plate  I,  figures  4,  8,  9, 10. 

SUBDIVISIONS  OF  PLATES  AND  FIGURES. 

If  a  plate  consists  of  two  or  more  parts  or  photographs  each  part 
should  be  marked  with  an  italic  capital  letter — A^  B^  etc. — which 
should  be  placed  directly  under  each.  If  it  is  made  up  of  many  parts, 
in  the  form  of  plates  that  accompany  reports  on  paleontology,  each 
part  should  be  similarly  marked  with  an  arable  numeral — 1,  2,  3,  etc. 
If  a  text  figure  is  subdivided  into  two  or  more  parts,  each  part  should 
be  marked  Avith  a  roman  capital — A,  B,  C,  etc.;  and  if  details  of  a 
part  are  to  be  described  each  detail  should  be  marked  by  an  italic 
lower-case  letter — a,  h,  <?,  etc. 

PREPARATION  OF  COPY  BY  AUTHORS. 

CHARACTER   OF    ORIGINAL   MATERIAL. 

In  the  Geological  Survey,  as  elsewhere,  the  "  originals  " — that  is, 
the  original  material  submitted  by  authors  for  the  illustration  of 
their  reports — differ  greatly  in  character  and  in  degree  of  clearness. 
Some  are  carefully  prepared ;  others  are  rough,  obscure  in  part,  and 
defective  in  detail.  Drawings  made  from  poor  originals  progress 
slowly,  because  the  draftsman  spends  much  time  in  interpreting  un- 
certain features  or  in  conference  with  the  author  concerning  details. 
An  original  should  be  perfectly  clear  in  detail  and  meaning,  so  that 
the  draftsman  can  follow  it  without  doubt.  It  should  not  consist  of 
parts  that  must  be  brought  together  to  make  a  new  drawing,  because 
the  result  of  the  combination  of  the  parts  will  be  uncertain  at  the 
outset  and  may  not  prove  satisfactory.  Each  original  illustration 
should  be  prepared  with  the  idea  that  the  draftsman  who  will  make 
the  finished  drawing  will  be  unfamiliar  with  the  subject  and  will  need 
definite  instructions;  all  data  should  be  plotted  and  each  figure  or 
plate  should  be  completely  made  up  before  it  is  submitted.  More  or 
less  roughly  prepared  originals  are  exi^ected,  but  they  should  show  no 
uncertainty  in  details.    Obscure  features  may  be  cleared  up  by  in- 


PREPARATION  OF  ILLUSTRATIONS.  13 

closing  the  features  in  penciled  loops  connected  by  a  line  with  notes 
written  on  the  margin,  such  as  "  omit  this  line,"  "  turn  at  an  angle 
of  30°  from  true  north,"  "  add,"  "  cut  out." 

PRELIMINARY  PREPARATION   OF  MAPS. 

The  base  map  that  generally  accompanies  a  report  may  be  an 
original  field  sheet  or  it  may  have  been  compiled  from  various  sources 
by  an  author  and  made  to  incorporate  the  results  of  his  field  work. 
It  should  not  be  a  collection  of  maps  of  different  scales  and  stand- 
ards to  be  worked  into  a  new  map. 

The  source  of  the  data  shown  on  every  original  base  map  should 
be  indicated  on  the  map,  whether  it  is  to  be  used  as  an  illustration 
or  as  a  record  of  field  work.  This  information  is  required  as  a  per- 
manent record  for  showing  the  reliability  of  the  map,  for  use  in  com- 
paring data,  and  for  giving  full  credit  to  those  who  are  responsible 
for  the  data.  An  author  should  see  that  this  requirement  is  observed 
in  order  that  proper  credit  may  be  given  and  should  especially  see 
that  all  cooperative  agreements  and  organizations  are  properly  men- 
tioned. 

An  original  map  should  preferably  be  complete  in  itself.  It  should 
not  consist  of  several  parts  or  sheets  unless  the  data  to  be  represented 
are  unusually  complex.  All  elaborate  or  technical  finish  of  border 
lines,  lettering,  or  like  features  should  be  left  to  the  draftsman  or  the 
engraver. 

Base  maps  that  involve  the  compilation  of  new  data  should  be 
prepared  by  either  the  topographic  branch  or  the  division  of  Alaskan 
mineral  resources.  If  a  base  map  already  published  is  to  be  reused 
it  should  be  submitted  to  the  chief  topographic  engineer  or  to  the 
chief  of  the  division  of  Alaskan  mineral  resources  for  approval. 
This  procedure  will  insure  a  single  standard  of  geographic  accuracy 
in  maps  appearing  in  Survey  publications. 

A  geologist  who  requires  a  base  map  that  includes  new  topographic 
data  should  address  a  request  for  its  preparation  to  the  chief  geolo- 
gist, who,  through  the  Director,  will  refer  the  request  to  the  topo- 
graphic branch.  The  request  must  be  accompanied  by  a  full  state- 
ment regarding  the  proposed  report  and  the  time  when  it  is  likely  to 
be  submitted.  The  preparation  of  such  base  maps  by  draftsmen  in. 
the  division  of  geology,  the  land-classification  board,  the  water- 
resources  branch,  or  the  section  of  illustrations  has  been  discon- 
tinued except  for  the  minor  adaptations  provided  for  above. 

If  a  report  requires  the  preparation  of  a  base  map  that  includes  no 
new  topographic  data  such  a  map  must  be  compiled  from  other  au- 
thentic maps  by  the  division  or  branch  in  which  the  report  originates. 


14  PREPARATION  OF  ILLUSTRATIONS. 

If,  however,  no  draftsmen  are  available  in  that  division  or  branch,  an 
arrangement  can  be  made  with  any  other  branch — as  tl\e  topogi-aphic 
or  publication  branch — ^that  may  have  draftsmen  available,  with  the 
understanding  that  the  cost  of  the  work  shall  be  reimbursed  to  the 
branch  doing  the  work  by  the  branch  ordering  it.  For  indicating 
geologic  and  other  data,  however,  an  author  may  make  use  of  an 
authentic  base  map  already  published,  and  after  it  is  reduced  or 
enlarged  to  appropriate  scale  by  photography  such  a  map  may  suffice 
for  transmittal  with  a  manuscript. 

MATERIAL   AVAILABLE   FOB  BASE    MAPS. 

The  maps  already  published  by  the  Geological  Survey  ^  and  other 
Government  bureaus  should  always  be  consulted  when  a  new  base  is 
to  be  compiled.  The  following  list  includes  most  of  the  maps  avail- 
able: 

1.  The  Survey's  regular  topographic  atlas  sheets,  published  on  three 
scales — 15-minute  sheets,  scale,  1:62,500;  30-minute  sheets,  scale, 
1 :  125,000 ;  60-minute  sheets,  scale,  1 :  250,000 — approximately  1  mile, 
2  miles,  and  4  miles  to  1  inch,  respectively — and  its  "  special "  maps,^ 
some  of  which  are  published  on  other  scales.  All  these  maps  can  be 
used  as  bases  for  detailed  geologic  maps,  for  compiling  maps  on 
smaller  scales,  and  for  revising  other  maps. 

2.  The  United  States  part  of  the  international  map  of  the  world, 
now  being  published  on  the  scale  of  1 : 1,000,000  (approximately  16 
miles  to  1  inch) .  Each  sheet  of  this  map  represents  an  area  measuring 
6°  of  longitude  and  4°  of  latitude.  The  published  sheets  of  this  map 
may  be  used  as  bases  for  general  maps.  The  sheets  are  drawn  on  the 
scale  of  1 :  500,000,  and  photolithographs  on  this  scale  are  available 
for  use  as  bases  for  geologic  or  other  maps. 

The  adaptability  of  the  1 : 1,000,000  scale  map  to  use  as  a  base  for 
general  geologic  maps  is  shown  in  the  geologic  maps  of  the  southern 
peninsula  of  Michigan  and  of  Indiana  in  Monograph  53  (Pis.  IV  and 
VII),  the  map  of  Florida  in  Bulletin  60  (PL  I),  and  the  map  of 
Vermont  in  Water-Supply  Paper  424  (PI.  I). 

3.  The  Survey's  two-sheet  wall  map  of  the  United  States,  49  by  76 
inches,  scale  1:2,500,000  (approximately  40  miles  to  1  inch).  Parts 
of  this  map  can  be  used  as  bases  for  general  geologic  or  other  maps 
and  as  copy  for  index  and  other  small  diagrammatic  maps.  This  map 
is  published  both  with  and  without  contours. 

4.  Land  Office  maps  and  township  plats.  These  maps  are  now 
being  published  on  a  scale  of  12  miles  to  1  inch ;  they  are  also  photo- 
lithographed  on  one-half  that  scale,  or  24  miles  to  1  inch.     The  town- 

»  a«^  "Topographic  maps  and  folios  and  geologic  folios  published  by  the  United  States 
OeologicaJ   SurTey  "    (latest  edition). 


PREPARATIOK  OF  ILLUSTRATIONS.  15 

ship  plats  are  printed  on  a  scale  of  one-half  mile  to  1  inch.  The  maps 
are  especially  useful  in  compiling  maps  in  which  land  lines  (townships 
and  sections)  are  essential,  and  the  township  plats  afford  valuable  de- 
tail and  are  useful  in  field  work  and  in  revising  other  maps.  Town- 
ship and  section  lines  should  appear  on  all  land-classification  maps 
published  by  the  Survey.  On  maps  on  a  scale  less  than  1 :  250,000  only 
the  townships  should  be  shown;  on  maps  on  scales  greater  than 
1 :  250,000  the  sections  should  be  shown ;  on  maps  on  a  scale  of 
1:250,000  the  sections  should  be  shown,  unless  their  representation 
will  materially  impair  the  legibility  of  the  map,  in  which  case  only 
the  townships  should  be  shown.    (See  fig.  1.) 

5.  Post-route  maps,  covering  single  States  or  groups  of  adjacent 
States,  published  on  sheets  of  different  sizes  and  on  scales  deter- 
mined mainly  by  the  size  of  the  State.  The  map  of  Texas  is  pub- 
lished on  a  scale  of  12  miles  to  1  inch,  that  of  Virginia  on  a  scale 
of  7  miles  to  1  inch,  and  that  of  West  Virginia  on  a  scale  of  6  miles  to 
1  inch.  Both  the  Land  Office  and  the  post-route  maps  are  useful  for 
reference  in  compiling  maps  on  smaller  scales.  Post-route  maps  are 
especially  useful  for  comparing  and  verifying  the  location  of  cities, 
towns,  and  railroads. 

6.  Coast  and  Geodetic  Survey  charts,  published  on  scales  that  are 
governed  by  the  area  represented  and  the  amount  of  detail  to  be 
shown.  These  maps  should  always  be  used  in  compiling  and  cor- 
recting coast  lines. 

7.  Maps  and  charts  published  by  the  Corps  of  Engineers  of  the 
Army,  the  Mississippi  River  Commission,  the  surveys  of  the  Great 
Lakes,  and  the  boundary  surveys.  These  maps  are  especially  useful 
if  the  scale  of  the  map  to  be  compiled  requires  considerable  detail. 

8.  The  Survey's  three  small  base  maps  of  the  United  States — (a) 
a  map  18  by  28  inches,  scale  110  miles  to  1  inch,  which  is  published 
both  with  and  without  contours,  or  with  relief  or  hypsometric  shad- 
ing; (h)  a  map  11  by  16  inches,  scale  190  miles  to  1  inch;  (c)  a  map 
7^  by  12  inches,  scale  260  miles  to  1  inch,  designed  for  use  as  a  two- 
page  illustration  in  a  bulletin  or  a  water-supply  paper. 

9.  The  Century,  Rand  McNally  &  Co.'s,  Cram's,  Stieler's,  The 
Times,  Johnston's  Royal,  and  county  atlases. 

10.  State  and  county  maps. 

11.  Railroad  surveys,  which  are  useful  in  furnishing  data  for  ele- 
vations as  well  as  for  locations  of  towns  and  stations. 

12.  The  latest  national-forest  maps  and  proclamations.  It  is, 
however,  not  necessary  that  national  forests,  bird  reservations,  and 
national  monuments  be  shown  on  a  map  in  a  report  unless  their 
addition  is  specially  requested  by  the  author  or  by  the  chief  of  the 
branch  submitting  the  report,  and  they  should  not  be  shown  if  they 
will  obscure  other  more  important  data. 


16 


PREPARATION  OF  ILLUSTRATIONS. 


The  principal  meridian 


h-- 


F 


6 

5 

4 

3 

SECTION 

2 
640  acres 

:i6o 
acre" 

7 

8 

9 

10 

11 

12 

18 

17 

16 

15 

14 

13 

19 

ZO 

21 

22 

23 

24 

30 

29 

28 

27 

26 

25 

31 

32 

33 

34 

35 

36 

DIAGRAM   OF  TOWNSHIP 


-Township  numbers 


FrcuRB  1. — Diagrams  showing  principal,  guide,  and  auxiliary  meridians,  standard  and 
special  parallels  and  correction  lines,  and  system  of  numbering  townships,  ranges, 
and  sections. 


PREPAEATION   OF  ILLUSTEATIOITS.  17 

The  Survey  has  published  numerous  maps  of  parts  of  Alaska, 
as  well  as  other  maps,  which  are  available  for  use  or  reuse  in  its  re- 
ports. Copies  of  all  base  maps  for  which  copper  plates  have  been 
engraved  by  the  Survey  can  be  obtained  on  requisition,  and  their  use 
in  a  new  report  will  save  time  as  well  as  the  cost  of  engraving.  Other 
maps  will  be  found  in  the  Survey  library,  where  the  latest  editions 
only  should  be  consulted. 

BASIC  FEATURES  OF  MAPS. 

It  must  be  remembered  that  "  every  map,  whatever  its  scale,  is  a 
reduction  from  nature  and  consequently  must  be  more  or  less  gen- 
eralized."* The  degree  of  generalization  in  the  geologic  and  other 
detail  to  be  shown  on  a  map  usually  involves  a  corresponding  degi'ee 
of  generalization  in  its  base.  Absolutely  true  generalization  means 
the  same  degree  of  omission  of  detail  for  each  kind  of  feature.  If  a 
base  map  on  a  scale  of  1  mile  to  1  inch,  prepared  with  the  usual 
detail,  were  placed  before  a  camera  and  reduced  to  a  scale  of  16  miles 
to  1  inch,  the  lines  representing  the  smaller  tributaries  of  streams  and 
the  smaller  water  bodies,  as  well  as  many  other  features,  would  prob- 
ably be  so  greatly  reduced  in  length  as  to  be  illegible.  If  from  this 
reduced  photograph  a  new  map  were  prepared,  from  which  all 
features  not  plainly  discernible  were  omitted,  the  new  map  should 
represent  what  might  be  called  true  generalization.  This  degree  of 
generalization  is,  however,  not  practicable,  but  unessential  detail 
should  be  systematically  omitted.  The  amount  of  detail  which  a  base 
map  should  show  is  limited  by  its  scale,  by  the  character  of  the  coun- 
try' it  represents,  and  by  the  kind  of  data  to  be  shown.  Coordinate 
features  of  a  topographic  map  should  be  shown  with  equal  detail. 
Detail  in  culture  may  call  for  detail  in  drainage,  though  relief  may 
be  greatly  generalized  or  entirely  omitted ;  detail  in  relief  may  like- 
wise call  for  detail  in  drainage,  though  culture  may  be  more  gen- 
eralized. 

•  If  the  three  fundamental  features  of  a  topographic  map — the  cul- 
ture, the  drainage,  and  the  relief — are  to  be  engraved  or  photo- 
lithographed  separately  and  printed  in  colors,  the  best  results  can  be 
obtained  by  drawing  each  feature  in  a  separate  color  on  one  sheet  unless 
the  work  is  coarse  and  great  precision  in  register  is  not  needed.  The 
culture  should  be  drawn  in  black  waterproof  ink,  the  drainage  in 
Prussian  blue,  and  the  relief  in  burnt  sienna;  but  care  should  be 
taken  that  the  colors  used  will  photograph  well.  To  insure  a  good 
photograph  it  is  usually  necessar}^  to  add  a  little  black  to  the  blue  and 
brown.    (See  "  Inks,"  p.  25.)    The  i^hotographer  will  then  make  three 

*  Gannett,  Henry,  A  manual  of  topographic  methods :  U.  S.  Geol.  Survey  Mon.  22,  p. 
107,  1893. 

861754°    -49 2 


18  PREPARATION   OF   rLLXJSTRATIOlsrS, 

negatives  and  will  opaque  or  paint  out  all  but  one  of  the  three  features 
on  each  negative.  The  cost  is  somewhat  greater  than  that  of  repro- 
ducing three  separate  drawings,  but  the  result  gives  more  accurate 
register  than  if  the  drawings  were  made  on  separate  sheets,  which 
are  likely  to  change  in  size  before  they  are  reproduced. 

STANDARD  SCALES. 

The  standard  scales  of  the  maps  used  in  the  publications  of  the 
Geological  Survey  are  fractions  or  multiples  of  1 : 1,000,000  (see 
p.  14),  except  for  a  map  that  is  reduced  expressly  to  fit  one  or  two 
pages  of  a  report  or  that  is  reduced  horizontally  or  vertically  to  lit 
the  text  as  a  small  diagrammatic  or  index  map.  It  should  be  re- 
membered that  a  map  which  may  be  serviceable  for  use  in  compiling 
a  new  map,  except  as  to  scale,  can  be  reduced  or  enlarged  to  the 
scale  of  the  new  drawing  by  photography,  by  a  pantograph,  or  by 
other  means,     (See  p.  47.) 

Maps  compiled  by  an  author  should  be  prepared  on  a  scale  of  at 
least  1^  times  and  preferably  twice  the  size  of  the  scale  used  on  the 
published  map.  Maps  traced  on  linen  sliould  be  no  less  than  twice 
the  size  of  publication.  Not  only  is  the  quality  of  the  reproduction 
improved  by  considerable  reduction,  but  the  larger  scale  of  the 
drawing  facilitates  the  plotting  of  details.  It  should  be  remembered, 
however,  that  a  linear  reduction  of  one-half  produces  a  map  only 
one-fourth  the  area  of  the  original,  and  reduction  so  great  may 
prevent  the  addition  of  data,  such  as  an  extended  note  in  small  letters 
applying  to  a  small  area  on  the  face  of  a  map,  which  would  not  be 
legible  when  reduced. 

ORIENTATION  OF  MAPS. 

A  map  that  bears  no  arrow  indicating  north  is  supposed  to  be 
oriented  north  and  south,  and  its  title  should  read  from  west  to  east. 
If,  however,  the  area  mapped  has  a  general  trend  in  one  direction, 
as  northwest  to  southeast,  and  its  squaring  up  by  a  north-south  line 
would  leave  too  much  blank  paper,  this  general  rule  is  not  followed. 
The  border  lines  on  such  a  map  should  conform  to  the  general  trend 
of  the  area  mapped,  an  arrow  should  show  north,  and  the  title  and 
scale  should  be  placed  horizontally,  but  the  projection  numbers  and 
town  names  should  follow  the  direction  of  the  parallels  of  latitude. 
(See  Pis.  X  and  XII,  Bull.  G28;  and  Pis.  VI,  XV,  and  XVI, 
Mon.  52.) 

PROJECTION.' 

The  poly  conic  projection  has  been  adopted  by  the  Geological  Sur- 
vey for  its  topographic  atlas  sheets  and  must  be  consistently  used 

*  See  also  pp.  43-45,  where  the  method  of  projecting  a  map  is  more  fully  explaioed. 


PREPARATION  OF  ILLUSTRATIONS.  19 

for  its  other  maps.  If  a  new  map  is  to  be  compiled  an  accurate 
projection  should  first  be  constructed,  and  no  plotting  should  be  done 
on  it  until  the  projection  has  been  checked  and  found  to  be  correct. 
A  projection  should  be  checked  or  proved  by  some  one  other  than 
the  person  who  prepared  it.  Next  the  drainage  and  the  water  areas 
should  be  outlined;  then  the  cultural  features  should  be  added;  and 
finally  the  relief,  whether  expressed  by  contour  lines,  hachures,  or 
shading.' 

EXPLANATION. 

Under  the  heading  "  Explanation  "  should  be  placed  all  matter 
needed  to  describe  fully  the  details  of  an  illustration,  whether  map, 
diagram,  or  section,  so  that  if  the  illustration  became  detached  it 
would  be  a  complete  self-explanatory  unit. 

The  explanation  of  a  map  may  be  placed  inside  the  border  lines 
if  there  is  ample  room  for  it,  or  it  may  be  placed  outside.  The  stand- 
ard arrangement  for  an  outside  explanation  for  geologic  maps  is 
shown  in  the  geologic  folios,  which  should  be  followed  in  general 
form.  If  there  is  space  within  the  border  lines  the  explanation  may 
be  appropriately  arranged  therein,  either  in  a  vertical  column  or 
horizontally,  according  to  the  size  and  shape  of  the  space  available. 
If  the  sequence  of  formation  is  shown  by  horizontal  arrangement  the 
younger  formations  are  placed  at  the  left  and  the  older  at  the  right. 
If  it  is  shown  by  a  vertical  arrangement  the  youngest  formation  is 
placed  at  the  top. 

Each  original  map  submitted  by  an  author  should  have  at  least 
4|  inches  of  blank  margin  on  the  right  and  at  the  bottom  in  which 
to  place  the  explanation,  scale,  title,  and  other  matter,  but  the  author 
should  make  no  attempt  to  elaborate  these  features  nor  should  he 
employ  a  draftsman  to  letter  them  carefully.  Plainly  written  ordi- 
nary script  is  quite  sufficient  for  original  maps;  the  final  lettering, 
which  may  consist  entirely  of  impressions  from  type,  will  be  added 
after  submittal  of  a  report. 

TITLES  OF  MAPS  AND  OTHER  ILLUSTRATIONS. 

The  titles  of  maps  should  be  supplied  by  authors  but  are  subject 
to  revision  in  order  to  make  them  agree  with  established  forms. 
They  should  be  written  in  ordinary  script,  not  carefully  lettered. 
They  should  state  concisely  the  kind  of  map^  the  area  shown,  the 
special  features  represented,  and  the  county.  State,  or  Territory  in 
which  the  area  is  located.  (See  p.  58.)  Titles  are  reproduced  directly 
only  on  lithographs,  three-color  prints,  photogelatin  plates,  and 
other  illustrations  that  are  printed  by  contractors,  not  by  the  Gov- 
ernment Printing  Office.    The  titles  of  illustrations  that  are  repro- 

*  See  pp.  46-48  for  methods  of  tracing  and  transferring. 


20  PREPAKATION   OF   ILLUSTRATIOITS. 

duced  by  relief  processes,  such  as  zinc  etching,  half  tone,  and  wax 
engraving,  are  printed  at  the  Government  Printing  Office  from 
type,  and  proofs  are  submitted  to  the  authors  for  examination. 

SYMBOLS  USED  ON  MAPS. 
GENEEAL  FEATXTRES. 

More  than  200  symbols  have  been  used  on  maps  to  express  25  dif- 
ferent kinds  of  data,  a  fact  indicating  at  once  a  notable  lack  of  uni- 
formity and  a  need  of  standardization.  It  is  of  coui-se  impossible  to 
provide  a  characteristic  symbol  that  can  be  used  uniformly  for  each 
kind  of  feature,  and  therefore  the  same  symbol  may  be  used  on  dif- 
ferent maps  to  express  different  things.  The  symbols  shown  in 
Plate  II  are  those  most  used  on  geologic  maps.  The  symbols  for 
dip  and  strike,  fault  lines,  mine  shafts,  prospects,  and  several  others 
are  generally  well  known,  but  on  some  maps  it  may  be  necessary  to 
modify  a  standard  symbol  to  express  additional  distinctions.  The 
symbols  shown,  however,  will  cover  all  the  ordinary  requirements  of 
miscellaneous  mapping.  Though  the  plate  shows  more  than  one 
symbol  for  some  features  the  symbol  most  commonly  used  is  given  first 
and  should  be  preferred.  The  center  of  each  symbol  should  mark 
the  location  of  the  feature  symbolized.  Symbols  are  not  always 
platted  with  sufficient  care.  On  small-scale  maps  they  are  difficult 
to  locate  and  unless  great  care  is  taken  in  platting  them  they  are 
likely  to  be  several  miles  out  of  place.  All  symbols  should  be  located 
precisely  where  they  belong. 

The  symbol  showing  dip  and  strike  should  be  accurately  platted 
b}'^  means  of  a  protractor,  so  that  the  strike  will  be  shown  graphi- 
cally, without  a  number  and  a  degree  mark,  and  not  need  replatting 
by  a  draftsman  or  engraver.  The  dip.  however,  should  be  indicated 
by  a  number  and  a  degree  mark. 

LETTER    SYMBOLS. 

The  letter  symbols  used  on  most  geologic  maps  to  indicate  the 
ages  and  names  of  the  formations  represented  consist  of  two  or  more 
letters — an  initial  capital  letter  for  the  name  of  the  system  and  one 
or  more  lower-case  letters  for  the  name  of  the  formation  or  of  the 
material,  as  Qt  (Quaternary — lower  terrace  deposits) ;  Cpv  (Car- 
boniferous— Pottsville  formation)  ;  -GOk  (Cambrian-Ordovician — 
Knox  dolomite),  etc.  The  standard  usage  for  this  feature  is  shown 
in  the  geologic  folios  but  is  subject  to  modification  in  other  publi- 
cations. 

In  preparing  an  original  geologic  map  a  letter  symbol,  such  as  has 
been  just  described,  or  a  number  should  be  put  in  the  proper  place 


U.  a  GEOLOGICAL  SURVEY 


PREPARATION  OF  ILLUSTRATIONS    PLATE  II 


Geologic  boundaries _. 

Inferred  boundaries  _ 

Known  fault 

Probable  or  inferred  fault 

Concealed  fault 
(covered  by  later  deposits) 

Fault  zone,  shear  zone 

Dip  of  fault  plane j 

'7o° 

Vertical  fault q 

Overlhrust  side  of  thrust  fault ...  _^____ 

Upheaved  side  of  normal  fault 

Downdropped  side  of 

ncrw.al  fault _  — — ^_  , 

Strike  and  dip  of  bedding /C'*^°      /( 

Strike  of  vertical  strata y 

Horizontal  beds 0 

Strike  and  dip  of  overturned  beds . .  o^so  ° 

Prevailing  dip  of  beds „    / 

Strike  and  dip  of  schistosity Z^'*^' 

Strike  of  vertical  schistosity >" 

Strike  and  dip  of  Joint  planes  —     y^ 

Strike  of  vertical  joint  planes  —      y^ 

Rock  exposure  v/ithout  ^. 

observed  strike  and  dip "^^ 

Rock  exposure  with  s\s 

observed  strike  and  dip *^ 

Rock  exposure  with  strike  ^ 

and  dip  of  schistosity ^^ 

General  dip  of  beds  having' 

subordinate  folds ^ 

Anticline  with  observed  pitch 11 

Syncline  with  observed  pilch ^^ 

Axis  of  anticline i 

Axis  of  syncline 1 

Axis  of  overturned  anticline /^ 

Axis  of  overturned  syncline yx 

Axis  of  plunging  anticline 

showing  direction  of  pitch j, 

Axis  of  plunging  syncline 

showing  direction  of  pitch ^ 

Glacial  striae /n^ 

Mine    shaft H     ^ 

Inclined  shaft --'\ 

Tunnel  opening  on  maps 

of  large  scale 7^ 

Mine  tunnels, 
showing  direction ^  z.-:^ (. 

Raises CD     EH      a     = 

Winzes _ .._  a        iii;ii|iiii 

Mine  workings — j' 

Mines  or  quarries ^    ^ 


Abandoned  mine  or  quarry 'K' 


Placer  mine,  surface  mine X 

Abandoned  placer  or 

surface  mine X         X 

Prospect  ► ^ 

Mine  pits _   crO  c=: 

Mine  dump Jj|J/   ^i>x 

Drillhole... O 

Inclined  drill  hole, 
showing  direction. — ^x 

WATER  WELLS 

Well,  character  not  indicated O 

Nonfiowing  well O 

Flowing  well 9 

Unsuccessful  or  dry  well (p 

Nonfiowing  well.  ^ 

with  pumping  plant ^ 

Flowing  well,  with  — . 

pumping  plant 


Spring _  •> 

Thermal  spring "T 

Mineral  spring  _ ^ 

OIL  AND  GAS  WELLS 
Site  for  test  well + 

Location  of  well O 

We/l  being  drilled O 

Dry  hole -<J> 

Dry  hole,  with  show  of  oil -^ 

Dry  hole,  with  show  of  gas ^ 

Dry  hole,  with  show  >j< 

of  oil  and  gas ' 

Oil  vjsll • 

Oil  well,  with  show  of  gas ■♦■ 


Abandoned  oil  well 

Abandoned  oil  well, 
with  show  of  gas-- 


Gas  well -J^ 

Gas  well,  with  show  of  oil -^ 

Abandoned  gas  well ^ 

Abandoned  gas  well,  X 

with  show  of  oil t 

Oil  and  gas  well -^ 

Abandoned  oil  and  gas  well -»■ 

Oil  tanks 


O^':- 


COAL   OUTCROP   SYMBOLS 
(usually  shown  in  color) 

Goal  outcrop  (dotted  line  hypotheticJ) 
Exposure  or  bloom  on  coal  outcrop 
Drift  or  slope  on  coal  outcrop  .. 


SYMBOLS  USED  ON  GEOLOGIC  MAPS,  ECONOMIC  MAPS, 
AND  MINE  PLANS 


PREPAEATION   OF  ILLUSTRATION'S.  21 

in  the  explanation,  and  the  same  sj-mbol  or  number  should  be  repeated 
at  one  or  more  places  on  the  map  within  the  areas  to  which  it  refers. 
Each  area  that  is  indicated  by  a  color^  should  be  marked  with  the 
proper  symbol  in  order  to  make  its  identification  sure,  for  light  colors 
especially  are  likely  to  fade  and  mixed  colors  can  not  be  discrim- 
inated with  certainty. 

OIL    AKD    GAS    SYMBOLS. 

A  complete  set  of  symbols  for  maps  showing  oil  and  gas  is  given 
on  Plate  II.  Referring  to  these  symbols  the  chief  geologist,  in  a 
memorandum  to  the  Director,  writes: 

The  symbols  used  by  tbe  Survey  in  its  oil  and  gas  maps  have  not  been  in 
accord  with  those  used  by  the  oil  companies,  nor  have  they  been  vpholly  logical. 
It  appears  that  though  they  were  submitted  for  recommendation  they  never 
have  been  formally  approved. 

Herewith  I  submit  a  code  prepared  by  the  geologists  of  the  oil  and  gas 
section.  They  conform  largely  to  commercial  use  and  embrace  its  best  features 
as  well  as  the  best  and  most  logical  features  of  our  previous  usage,  the  de- 
partures from  which  are,  after  all,  of  minor  consequence. 

The  symbols  here  submitted  [see  PI.  II]  with  recommendation  for  approval 
are  founded  on  a  building-up  system,  so  that  the  history  and  the  results  of  drill- 
ing at  any  location  can  be  recorded  by  slight  additions  to  symbol  and  without 
erasure.    Thus  maps  may  be  revised  without  scratching. 

In  drawing  these  symbols  the  draftsman  should  make  the  rays  of  the  gas 
well  distinct  and  in  adding  the  vertical  bar  or  line  showing  that  a  hole  is 
dry  or  abandoned  should  make  it  long  enough  to  be  distinct.  It  would  be  prefer- 
able to  draw  this  bar  obliquely,  but  an  oblique  position  would  coincide  with 
some  of  the  patterns  on  certain  maps,  and  it  should  therefore  be  placed  verti- 
cally. The  vertical  line  indicates  the  failure  or  abandonment  of  the  well, 
the  symbol  for  which  is  thus  scratched  off  or  canceled  by  the  line  dravpn  through 
it.  The  symbols  agree  so  far  with  commercial  usage  that  oil  men  will  have 
little  need  to  consult  the  explanation. 

SYMBOLS  FOR  USE  ON  MAPS  SHOWING  FEATURES  OF  GROUND  WATER. 

The  symbols  used  on  maps  relating  to  ground  water  represent  the 
features  named  below,  each  of  which  has  been  shown  in  publications 
already  issued. 

Area  of  absorption  or  outcrop.  Area  that  discharges  ground  water. 

Depth  to  water  table.  Quality  of  ground  water. 

Contours  of  water  table.  Area  irrigated  with  ground  water. 

Fluctuation  of  water  table.  Nonflowing  well. 

Depth  to  water-bearing  formation.  Flowing  vrell. 

Structure  contours  of  water-bearing  Unsuccessful  or  dry  well, 

formation.  Well  with  pumping  plant. 

Area  of  artesian  flow.  Spring. 
Head  of  artesian  water. 

The  lack  of  uniformity  in  the  symbols  commonly  employed  to  rep- 
resent these  features  is  due  to  differences  in  the  number  of  colors  used 
on  the  maps  and  differences  in  the  scale.     Standard  colors  for  the 


22  PREPARATION  OF  ILLUSTRATIONS. 

larger  features,  such  as  those  for  areas  of  artesian  flow,  areas  of  ab- 
sorption, and  curves  showing  depths  to  water  table  or  to  water-bearing 
formations,  can  not  be  fixed,  because  of  considerations  of  economy  in 
printing.  For  example,  if  light  green  is  the  standard  color  to  be  used 
for  delineating  areas  irrigated  by  ground  water  and  no  green  is  used 
on  other  j^arts  of  the  map  its  use  would  represent  an  additional  or 
special  printing,  whereas  a  tint  of  blue,  brown,  or  purple,  if  any  of 
these  colors  is  used  for  other  features  or  the  map,  might  be  used 
also  for  this  feature  without  additional  printing.  Therefore  the 
general  use  of  any  particular  color  for  a  water  feature  seems  to 
be  impracticable;  but  this  fact  should  not  preclude  the  adoption  of 
color  standards  for  use  subject  to  the  requirements  of  economy  in  pub- 
lication. 

The  ordinary  symbols  for  wells  are  the  open  circle  and  the  solid 
circle,  or  dot.  Only  in  the  secondary  or  specific  well  symbols  does 
there  appear  to  be  lack  of  uniformity,  the  choice  of  secondary  symbols 
being  governed  either  by  personal  preference  or  by  the  requirements 
for  specific  distinction. 

All  symbols  should,  if  possible,  suggest  the  things  they  represent. 
Wells  are  circular  and  hence  the  open  circle  is  most  used  and  most 
appropriate  for  nonflowing  wells.  To  indicate  a  flowing  well  the 
circle  is  made  solid,  denoting  that  the  well  is  full  of  water.  For  an 
unsuccessful  well  the  most  suggestive  symbol  would  be  an  open  circle 
with  a  line  drawn  through  it  to  denote  cancellation.  It  has  been 
suggested  that  if  water  features,  including  wells,  are  to  be  printed  in 
blue,  unsuccessful  wells,  or  dry  holes,  be  printed  in  black.  A  large 
circle  drawn  around  the  symbol  for  a  flowing  or  nonflowing  well  will 
appropriately  denote  a  pumping  plant  at  the  well. 

The  accepted  symbol  for  a  spring  is  a  dot  with  a  waved  tail  repre- 
senting the  direction  of  flow,  if  known.  Tliis  symbol  can  not  be 
modified  without  destroying  its  prime  characteristics,  but  it  may  be 
accompanied  by  a  letter  indicating  the  kind  of  spring.  An  open 
circle  wnth  a  tail  might  be  used  on  large-scale  maps,  but  it  would  be 
out  of  scale  on  other  maps,  whereas  the  black  or  blue  dot  and  tail  will 
fit  maps  of  any  scale. 

The  following  colors  and  symbols  can  most  appropriately  be  used 
to  represent  ground-water  features.  The  well  and  spring  symbols 
can  be  varied  by  adding  letters  if  they  are  necessary  to  express  other 
data  than  those  indicated  in  the  list  below. 

General  ground-water  features. 

Area  of  absorption  or  outcrop:  Flat  color  used  on  the  map  to  show  the  geologic 

system  in  which  the  absorbing  formation  occurs. 
Areas  showing  depths  to  v/ater  table:  Shades  of  purple  and  gray;  if  possible 

the  shades  showing  the  areas  of  least  depth  should  be  darkest  and  the  shades 

should  grade  from  those  to  lighter  tints. 


PREPARATION  OF  ILLUSTRATIONS.  23 

CJontours  of  water  table,  or  contours  on  water-bearing  formations:   Gray  or 

purple  curves  or  lines. 
Areas  of  artesian  flow :  Blue  flat  tint,  or  fine  ruling  in  blue.     Depth  to  water- 
bearing formations:  Gradation  of  a  single  color  or  of  two  related  colors  from 

dark  for  shallow  depths  to  light  for  greater  depths. 
Nonflowing  artesian  areas   (pumped  wells)  :  Green  flat  tint,  or  fine  ruling  in 

green.     Depth   to  water-bearing  formations  shown  by   gradation   of  tint   if 

possible  from  dark  for  shallow  depths  to  light  for  greater  depths. 
Head  of  artesian  water :  Blue  curves  or  lines. 

Areas  that  discharge  ground  water :  Blue  flat  tint,  or  fine  ruling  in  blue. 
Areas  irrigated  with  ground  water:  Green  flat  tint,  or  fine  ruling  in  green. 

O     Well,  character  not  indicated. 

O     Well,  nonflowing. 

^     Well,  flowing. 

A,     Well,  unsuccessful  or  dry. 

(g)    Well,  nonflowing,  with  pumping  plant. 

@    Well,  flowing,  with  pumping  plant. 
1 9     Springs. 

•T     Spring,  thermal. 

•M     Spring,  mineral. 

The  standard  color  scheme  should  be  used  if  no  conditions  preclude 
its  use,  but  if  other  colors  can  be  used  with  greater  economy  with- 
out sacrificing  clearness  the  use  of  the  standard  colors  should  be 
waived. 

BLACK-LINE    CONVENTIONS. 

A  complete  set  of  the  black-line  j)atterns  used  to  distinguish  areas 
on  a  map  is  given  in  Plate  VIII  (p.  60),  and  their  application  to 
a  finished  drawing  is  shown  in  figure  9  (p.  62).  These  patterns, 
however,  should  preferably  not  be  used  by  the  author  in  his  prelimi- 
nary work  on  an  illustration.  For  this  purpose  water  colors  or 
colored  crayons  are  preferable,  and  the  distinctions  between  areas 
may  be  emphasized  by  letter  symbols, 

MATERIALS  USED  IN  PREPARING  MAPS. 
PAPEH. 

For  large  and  important  maps  which  may  at  some  time  be  ex- 
tended to  cover  a  greater  area  or  which  may  be  made  to  fit  maps 
already  prepared  or  published  the  paper  used  should  be  mounted  on 
muslin  to  reduce  to  a  minimum  the  shrinking  or  stretching  caused  by 
atmospheric  changes.  Pure  white  paper  produces  a  better  negative 
than  a  cream  or  yellowish  paper  and  will  retain  its  color  longer,  but 
all  papers  become  more  yellow  with  age  and  exposure  to  light. 

The  following  brands  of  paper  are  used  in  the  Survey  in  the 
preparation  of  maps : 

"  Normal "  K.  &  E.,  unmounted.  Has  an  excellent  surface  and 
comes  in  flat  sheets,  19  by  24,  22  by  30,  and  27  by  40  inches. 


24  PREPARATION   OF   ILLUSTRATIONS. 

"  Paragon  "  K.  &  E.,  mounted  on  muslin.  In  10-yard  rolls  72 
inches  wide.  Used  in  the  Survey  for  large  office  drawings  and  maps 
of  large  scale. 

"  Anvil "  K.  &  E.,  mounted  on  muslin.  In  10-yard  rolls  42,  62, 
and  72  inches  wide.    Used  in  the  Survey  for  large  drawings. 

''  Whatman's  hot  pressed,"  unmounted  or  mounted  on  muslin.  In 
sheets  ranging  in  size  from  13  by  17  to  31  by  53  inches.  An  excellent 
paper  for  maps.  The  muslin-backed  paper  is  recommended  for  use 
in  preparing  large  detailed  maps  and  base  maps  that  are  to  be 
retained  as  permanent  records.  The  muslin  provides  a  durable  and 
flexible  backing  that  permits  the  map  to  be  rolled,  and  paper  thus 
mounted  is  particularly  serviceable  for  a  map  which  may  be  sub- 
jected to  considerable  revision  and  to  which  must  be  added  finally 
a  title,  explanation,  and  other  marginal  matter. 

"  Ross's  relief  hand-stipple  drawing  paper."  A  stiff  enameled  or 
chalk-coated  paper  whose  surface  has  been  compressed  into  minute 
points  that  stand  in  slight  relief  so  that  a  shade  made  on  it  with 
pencil  or  crayon  is  broken  up  into  dots  and  can  be  reproduced  by 
photo-engraving.  For  use  in  making  shaded  drawings,  drawings 
showing  relief  by  light  and  shade,  etc.  Similar  paper  is  prepared 
for  parallel-line  and  other  pattern  effects.  In  sheets  ranging  in  size 
from  11  by  14  to  22  by  28  inches.     (See  p.  51  for  method  of  using.) 

Profile  and  cross-section  paper.  In  sheets  of  convenient  sizes  or 
in  rolls.  Bears  lines  printed  in  blue,  green,  red,  or  orange,  in  many 
kinds  of  rulings,  which  may  be  selected  by  reference  to  catalogues. 
Profile  and  cross-section  paper  printed  in  orange  is  recommended  for 
preliminary  drawings;  blue  is  recommended  for  drawings  that  are 
made  in  pencil  and  submitted  for  inking  in. 

BBISTOL  BOABD. 

For  the  smaller  maps,  such  as  key  maps  and  maps  less  than  18  by  24 
inches,  and  for  small  drawings  made  for  direct  reproduction,  Rey- 
nolds's bristol  board  is  recommended  on  account  of  its  pure- white  color 
and  its  hardness,  which  permits  erasures  to  be  made  without  affect- 
ing redrawing  over  the  corrected  area.  It  is  obtained  in  2- ply,  3-ply, 
and  4-ply  sheets.  The  2-ply  and  3-ply  are  especially  useful  in  mak- 
ing delicate  brush  and  pencil  drawings  and  pen  and  ink  draw- 
ings. The  sizes  used  in  the  Survey  are  l^  by  20f ,  18^  by  22|,  and 
21^  by  28J  inches. 

TBACINO    LINEN. 

Tracing  cloth  or  linen  is  especially  useful  for  large  work  that  will 
require  considerable  reduction.  (See  p.  18.)  Its  advantages  are  that 
a  tracing  that  has  been  carefully  made  on  it  over  any  kind  of  copy  fori 
direct  reproduction  by  a  photo-engraving  process  can  be  used  fo; 


PREPARATION"  OF  ILLUSTRATIONS.  25 

making  a  paper  negative  for  contact  printing  or  blue  printing.  On. 
the  other  hand,  it  is  susceptible  to  atmospheric  changes  that  affect 
scale,  and  the  lines  traced  on  it  are  not  reproduced  as  sharply  as  those 
made  on  paper.    It  can  be  obtained  in  rolls  30  to  54  inches  wide. 

Erasures  should  be  made  on  tracing  linen  with  a  hard  rubber 
eraser,  not  with  a  sand  rubber  or  a  steel  eraser. 

IJTKS. 

The  best  drawing  inks  are  in  liquid  form,  ready  for  use.  They 
should  be  waterproof  and  equal  to  the  grade  known  as  Higgins's 
waterproof  ink.  When  a  suitable  waterproof  blue  ink  can  not  be 
obtained,  a  good  blue  for  features  of  drainage  can  be  made  by  dis- 
solving a  half  pan  of  Winsor  &  Newton's  prussian  blue  in  water.  No 
good  waterproof  burnt  sienna  ink  seems  to  be  obtainable,  but  a  good 
substitute  can  be  made  by  dissolving  Winsor  &  Newton's  water  color 
of  that  name. 

Ink  lines  should  be  drawn  in  fidl  strength  of  color — lines  that 
should  be  black  must  not  appear  grayish,  for  example — and  pens 
should  be  kept  clean.  The  same  pen  should  not  be  used  for  applying 
two  inks,  as  the  mixture  thus  produced  is  likely  to  thicken  or  coagulate 
on  the  pen.  A  little  black  should  be  added  to  colored  inks  that  are 
used  in  making  drawings  to  be  reproduced  in  colors  in  order  to 
strengthen  the  lines  for  photographic  reproduction, 

DKAWING  PENS. 

The  pens  made  by  Keuffel  &  Esser,  especially  their  No.  3202,  and 
Gillott's  Nos.  291,  290,  170,  and  303  give  complete  satisfaction.  The 
Gillott  numbers  are  given  in  the  order  of  fineness  of  the  points.  No. 
291  being  the  finest.  The  best  cleaner  for  a  drawing  pen  is  a  piece 
of  chamois  skin. 

PENCILS. 

Pencils  used  for  drawing  should  have  leads  of  a  quality  equal  to 
those  of  the  Koh-i-noor  brand,  in  which  the  grades  of  hardness  are 
indicated  by  3B,  2B,  B,  HB,  F,  H,  2H,  311,  4H,  5H,  6H.  7H,  8H, 
and  9H ;  the  softest  grade  is  3B  and  the  hardest  911.  The  grades  most 
generally  used  are  B,  HB,  F,  4H,  and  6H. 

BUBBEB  EBASERS  AND  CLEANERS. 

Two  kinds  of  rubber  erasers  are  usually  employed  in  making 
erasures  on  drawings — a  hard,  dense  rubber  like  the  "  Kuby,"  and  a 
soft,  pliable  rubber  like  the  ''Venus"  or  "H"  (Hardtmuth).  The 
soft  rubber  is  also  useful  for  cleaning  large  surfaces.  Art  gum  is 
also  recommended  for  this  purpose  and  has  the  advantage  of  not 
disturbing  the  surface  of  the  paper. 


26  PREPARATION    OF   ILLUSTRATIONS. 

COLOBED  PENCILS  AKD  CHATONS. 

Colored  pencils  and  crayons  are  useful  only  for  coloring  pre- 
liminary maps.  They  are  not  recommended  for  use  on  maps  that 
are  to  be  kept  for  reference  or  to  be  submitted  for  reproduction,  be- 
cause the  colors  rub  off,  but  they  can  be  used  on  photographic  prints  of 
base  maps  or  on  transparent  oversheets,  for  which  the  unglazed  side 
of  tracing  cloth  is  well  suited.  Wlien  they  are  so  used  register  marks 
should  be  added  at  numerous  points  on  the  map  and  the  oversheet,  in- 
cluding the  four  corners,  the  color  boundaries  should  be  drawn  or 
traced,  and  finally  the  colors  should  be  added.  Two  or  more  colors 
should  not  be  used  on  any  one  area  to  modif}'  a  tone,  but  each  area 
sliould  be  colored  with  a  separate  crayon.  Patterns  or  designs  should 
not  be  used  except  to  strengthen  contrasts,  and  for  that  purpose  a 
pattern  may  be  drawn  with  a  black  pencil  over  a  color. 

WATER   COLORS. 

By  dilution  to  half  strength  some  of  the  standard  water  colors  will 
yield  a  tint  or  hue  that  will  contrast  with  other  tints  or  hues  pro- 
duced in  the  same  way  quite  as  well  as  imdiluted  or  full  colors  will 
contrast  with  one  another.  The  colors  named  below,  except  chrome- 
j'ellow  and  emerald-green,  are  among  those  that  when  diluted  will 
afford  satisfactory  contrasts  among  themselves  and  with  their  full 
colors  and  are  recommended  for  use  in  coloring  original  maps. 

Mauve.  Hooker's  green  No.  2. 

Crimson  lake.  Emerald-green. 

Orange-vermilion.  Payne's  gray. 

Burnt  sienna.     >  rl"'-  Lampblack. 

Cadmium-yellow.  Sepia. 

Chrome-yellow.  Cerulean  blue. 
Olive-green. 

Other  pigments  spread  better  than  cerulean  blue  and  emerald-green, 
but  the  exceptional  purity  of  color  of  these  two  seems  to  warrant 
their  use. 

JAPANESE  TRANSPARENT  WATER  COLORS. 

Japanese  transparent  water  colors,  so  called,  are  used  by  some 
geologists.  They  spread  evenly  and  are  convenient  for  field  use,  but 
they  can  not  be  washed  out  like  other  water  colors,  so  that  when  they 
are  once  applied  to  an  area  and  a  change  of  color  becomes  necessary 
they  must  be  bleached  out.  A  good  bleach  is  sodium  hypochlorite, 
which  should  be  applied  with  a  brush  until  the  color  disappears,  and 
the  area  dried  with  a  blotter  before  recoloring.  Light  tints  of  these 
colors  are  believed  to  be  somewhat  fugitive  if  exposed  to  strong  light. 


PREPARATION   OF  ILLUSTRATIONS.  2T' 

COLORING  GEOLOGIC  MAPS. 

The  colors  used  on  most  original  maps  are  not  pleasing,  a  fact  that 
is  of  no  particular  importance,  but — and  this  is  of  importance — they 
often  fail  to  give  clear  distinctions ;  the  separate  areas  can  not  always 
be  identified  or  distinguished  with  certainty.  Again,  some  colors  are 
fugitive,  and  when  laid  on  in  light  tints  they  disappear  entirely  or 
become  uncertain.  Much  of  the  difficulty  in  identifying  and  discrimi- 
nating colors  on  an  author's  original  maps  is  due  to  the  promiscuous 
mixing  of  colors.  Many  persons  can  not  match  or  discriminate  mixed 
.or  broken  colors.  Hence  if  the  supply  of  a  color  produced  by  mixing 
becomes  exhausted  and  the  attempt  is  made  to  duplicate  it  by  a 
second  mixture  the  two  will  probably  fail  to  match.  It  is  therefore 
suggested  that  colors  in  full  strength  and  colors  diluted  to  half 
strength  be  used  instead  of  mixtures  of  two  or  more  pigments,  so 
that  one  color  in  two  strengths  or  tones  can  be  employed  to  indicate 
areas  that  are  to  be  distinguished.  The  colors  listed  on  page  26  will 
give  24  satisfactory  distinctions  and  will  thus  supply  all  demands  for 
map  coloring. 

To  insure  satisfactory  contrasts  between  colored  areas  on  a  map, 
unlike  colors  should  be  placed  next  to  each  other — that  is,  colors 
should  be  placed  together  that  are  widely  separated  in  the  spectrum, 
such  as  yellow  and  mauve,  red  and  green,  blue  and  orange,  burnt 
sienna  and  olive-green ;  not  such  as  red  and  orange,  blue  and  purple, 
orange  and  3'ellow,  sepia  and  burnt  sienna. 

A  sufficient  quantity  of  water  and  color  pigment  to  be  used  for  one 
formation  area  on  a  map  should  be  stirred  in  a  saucer  until  the  de- 
sired tint  is  produced  before  it  is  applied.  To  maintain  the  same  tone 
properly  the  color  should  be  well  stirred  every  time  the  brush  is 
filled ;  if  it  is  not  stirred  the  brush  will  on  the  next  dipping  take  up 
a  lighter  tint,  because  most  pigments,  especially  those  derived  from 
minerals,  tend  to  precipitate.  When  the  colors  are  applied  the  map 
should  preferably  be  placed  in  a  slightly  inclined  position,  and  the 
coloring  should  be  started  at  the  upper  boundaries  of  an  area  to  be 
colored,  the  well-filled  brush  being  pulled  toward  the  painter  and 
worked  rapidly  back  and  forth  horizontally,  the  edges  of  the  fresh 
color  being  kept  wet.  If  the  edges  are  allowed  to  dry,  a  hard  line 
and  a  smeared  or  imeven  effect  will  be  produced, 

A  strong  color  should  generally  be  used  for  small  areas  unless  the 
map  shows  also  large  areas  that  must  have  the  same  color;  lighter 
hues  should  be  used  for  large  areas.  Bright  colors  are  best  suited  for 
areas  of  igneous  roclvs,  dikes,  and  veins,  and  these  may  be  reduced  in 
strength  for  the  larger  areas. 

The  Survey's  color  scheme  (see  p.  63)  need  not  be  applied  at  this 
stage  of  preparation,  except  in  the  most  general  way.    Appropriate 


28  PREPAEATION    OF   ILLUSTRATIONS. 

final  colors  can  be  best  selected  when  the  new  map  is  made  ready  for 
engraving.  In  the  author's  original  maps  adequate  color  distinctions 
between  areas  are  more  important  than  the  use  of  standard  geologic 
colors.  Patterns  should  not  be  ruled  in  one  color  on  an  original  map 
to  indicate  distinctions  between  different  formations  of  the  same  age 
or  period,  because  such  patterns  are  difficult  to  produce  by  hand  with 
proper  uniformity  except  by  engraving. 

It  is  of  vital  importance  that  an  original  base  map  should  be  free 
from  colors  and  from  technical  symbols  in  order  that  it  may  be  kept 
clean  for  photographing  and  preserved  for  possible  future  use.  Such 
a  map  should  preferably  be  photographed  in  order  to  obtain  prints 
on  which  to  add  the  colors  and  symbols ;  the  use  of  an  oversheet  for 
this  purpose  is  not  nearly  so  satisfactory.  "When  photographed  a  base 
map  should  be  reduced  to  publication  scale  in  order  to  save  the  addi- 
tional cost  of  a  larger  negative,  and  this  reduced  map  may  be  made 
up  for  publication  by  the  addition  of  colors  and  symbols,  title,  expla- 
nation, etc. ;  but  the  lithographer  will  also  need  the  original  base  map 
from  which  to  make  his  reproduction. 

DIAGRAMS. 
ESSENTIAL  FEATTTEES. 

The  term  "  diagrams,"  as  used  here,  includes  such  illustrations  as 
mine  plans,  profiles,  sections,  stereograms,  and  maps  that  are  more 
diagrammatic  than  cartographic.  The  first  essential  in  the  original 
drawings  for  simple  diagrams  is  clearness  of  copy.  Simplicity  of 
subject  does  not  warrant  hasty  preparation,  for  an  original  sketch 
that  has  been  carelessly  drawn  and  is  inaccurate  or  inconsistent  in 
detail  may  lead  to  serious  errors.  Ruled  paper  printed  especially  for 
platting  profiles  and  cross  sections  should  be  used.  Curves  or  graphs 
made  by  an  author  with  pencil  on  blue-lined  section  paper  may  be 
inked  by  more  sldllful  draftsmen.  An  author's  pencil  sketches  are 
usually  satisfactory  if  they  indicate  plainly  the  facts  to  be  represented, 
but  they  should  be  prepared  with  some  care  as  to  detail.  Tables  and 
like  matter  are  not  generally  satisfactory  material  from  which  to  pre- 
pare drawings.  In  drawings  for  diagrams  that  are  to  be  printed  in  the 
text  as  figures  the  use  of  large,  solid  black  bars  or  of  conspicuous  areas 
of  solid  black  is  objectionable,  because  the  black  is  likely  to  print 
gray  and  to  appear  uneven  in  tone.  Ruled  tints  or  cross  lining  give 
better  effects.  Stereograms  should  be  prepared  by  an  author  with 
especial  care,  for  they  represent  facts  only  as  the  author  sees  them, 
and  the  author's  view  must  be  imparted  to  the  draftsman  graphically. 
The  "third  dimension" — the  relief — in  such  drawings  is  not  easily 
expressed  and  should  be  brought  out  clearly  in  the  author's  rough 
sketches. 


PREPARATION   OF  ILLUSTRATIONS. 


29 


For  illustrations  of  apparatus  photographs  are  preferred,  but 
if  rough  sketches  are  submitted  they  should  show  not  only  correct 
relations  but  all  dimensions. 

PLANS   OF   MINE   WORKINGS. 

Blue  prints  obtained  from  mining  companies  are  acceptable  for 
plans  of  mines  or  underground  workings,  but  all  unnecessary  or 
irrelevant  details  on  such  plans  must  be  canceled  and  all  essential  fea- 
tures retained,  and  every  essential  feature,  especially  any  added  data, 
must  be  clearly  interpretable.  Many  such  blue  prints  are  so  large  and 
unwieldy  that  they  must  be  greatly  reduced  by  photography  before 
they  can  be  redrawn.  If  the  lines  are  too  weak  to  photograph,  a  trac- 
ing of  the  essential  parts  can  be  made  and  reduced  to  about  twice 


Figure  2. 


-Conventional  lines  used  in  preparing  plans  and  diagrams  of  mine  workings  to 
distinguish  different   levels. 


publication  size.  The  shadowless  drafting  table,  described  on  pages 
47-48,  is  well  adapted  to  the  work  of  making  such  tracings.  Blue 
prints  can  also  be  pantographed  to  any  convenient  size  if  the  details 
are  not  too  minute  or  complex. 

The  levels  in  plans  of  underground  workings  can  be  differentiated 
in  finished  drawings  by  a  system  of  conventional  outlines  in  black, 
as  shown  in  figure  2,  by  conventional  patterns  or  symbols  within 
plain  outlines,  or  by  colors.  Such  plans  should  not  be  printed  in 
colors  unless  the  maze  of  workings  is  so  complex  that  lines  showing 
the  different  levels  would  become  confused  or  obscure  if  printed  in 
black. 

SECTIONS. 

The  standard  forms  of  geologic  sections  are  shown  in  the  geologic 
folios.    Structure  sections  should  be  prepared  with  great  care  as  to 


30 


PREPARATION  OF  rLLUSTRATTONS. 


detail  but  without  attempt  at  refinement  of  lines  and  letterino^.  The 
author's  drawing  of  a  section  along  a  line  or  zone  that  is  not  definitely 
indicated  by  a  line  on  an  accompanying  map  should  be  so  prepared 
that  it  may  be  copied  exactly.  On  the  other  hand,  the  draftsman,  in 
reproducing  a  section  that  represents  the  structure  along  a  given  line 
or  zone,  may  be  able  to  make  the  outcrops  coincide  with  the  topog- 
raphy and  the  formation  boundaries  shown  on  the  map,  but  the 
structure,  or  the  interpretation  of  it  to  be  given,  should  be  carefully 
worked  out  by  the  author.  All  essential  facts  relating  to  bedding, 
folding,  faulting,  crosscutting  dikes  and  veins,  or  other  significant 
details  should  be  indicated  with  precision.  No  attempt  need  be  made 
to  draw  firm,  steady  lines  so  long  as  the  essential  facts  are  clearly 
expressed. 

All  sections  should  be  drawn  to  scale,  and  both  the  vertical  and  the 
horizontal  scale  should  be  given  on  the  drawing.  These  scales  should 
be  uniform  if  possible,  or  at  least  the  vertical  exaggeration  should 
be  minimized.   Too  great  vertical  exaggeration  creates  distortion  and 


PiGDBE  3. — Section  and  perspective  view  showing  relations  of  surface  features  to  the 
different  kinds  of  rock  and  the  structure  of  the  beds. 


is  grossly  misleading.  Sections  should  be  drawn  to  scale  on  ruled 
paper  prepared  for  the  use  of  authors.  Such  paper  may  be  obtained 
on  requisition. 

A  kind  of  cross  section  which  is  not  often  used  but  which  gives  a 
more  pictorial  and  clearer  conception  of  underground  relations  than 
other  kinds  is  made  by  adding  a  sketch  of  the  topography  above  the 
section.  This  sketch  should  be  a  perspective  view,  in  which  the 
prominent  features  shown  hypothetically  in  the  section  below  it 
will  be  reflected  in  the  topography.  Such  a  sketch  might  show,  for 
example,  not  only  monoclinal  slopes,  "  hogbacks  "  due  to  steeply  up- 
turned beds,  terraces,  escarpments,  and  like  features,  but  volcanic 
necks  or  other  extruded  masses  in  their  true  relations  to  the  under- 
ground geology  of  the  country.  (See  fig.  3.)  In  submitting  the 
draft  of  such  an  illustration  the  author  should,  if  possible,  submit 
also  a  sketch  or  photographs  of  the  adjacent  country  and  indicate  on 
the  section  the  point  of  view  by  notes  such  as  "  Sketch  A  made  at 
this  point,"  "  See  photograph  B."  The  sketch  will  be  more  useful 
if  it  is  prepared  on  a  scale  consistent  with  the  details  of  the  section. 


PREPARATION   OF  ILLUSTRATIONS. 


31 


It  may  be  made  with  a  pencil  and  should  show  as  well  as  possible 
the  relations  of  the  features  in  the  landscape  to  those  in  the  section. 
Some  good  examples  of  illustrations  of  this  type  can  be  found  in 
Powell's  "  Exploration  of  the  Colorado  Kiver,"  pages  182-193.  One 
simpler  figure  of  the  same  kind  is  given  on  the  cover  of  the  geologic 
folios. 

In  preparing  original  drawings  representing  columnar  sections,  or 
sections  in  wells  or  ravines,  the  author  should  indicate  all  well-defined 
or  important  local  features  of  structure,  such  as  cross-bedding,  ore 
bodies,  or  lenses.  If  there  are  no  unusual  features  or  details,  the  sub- 
divisions need  be  identified  only  by  names  of  materials,  such  as  "  thin- 
bedded  limestone,''  or  "slates  with  some  coal,"  the  coal  beds  being 
shown.    The  sections  should,  however,  be  so  plotted  and  subdivided  by 


EXPLANATION 


CoaL       Cannel  coal   Bony  coal 


Bone     Carbonaceous     Shaly 
shale         Kmestone 
Vertical  scale 

SO  10 

'■■'•■''  T  • 


Clay 


LimeatDne 


to  Feet 


FiGUEB  4. — Sections  of  coal  beds.  The  figure  shows  the  publication  size  and  the  arrange- 
ment of  the  sections.  Each  section  should  be  drawn  three-tenths  or  four-tenths  of  an 
inch  wide  and  reduced  one-half.  Thickness  can  be  indicated  by  numbers,  as  shown 
on  sections  1  and  10,  or  by  bar  scale. 

the  author  that  each  section  or  group  of  sections  will  be  complete  in 
its  crude  form.  The  compilation  of  various  parts  into  one  unit  and 
the  construction  of  columnar  sections  by  reference  to  tables  alone  is 
an  essential  part  of  the  author's  original  preparation. 

Sections  designed  to  show  the  relative  thickness  of  beds  of  coal, 
arranged  in  groups  for  publication  either  as  plates  or  figures,  should 
be  drawn  in  columns  three  or  four  tenths  of  an  inch  wide  and  reduced 
one-half,  as  shown  in  figure  4.  These  sections,  whether  correlated 
or  not,  should  be  drawn  to  some  definite  vertical  scale  and  should 
show  the  thickness  of  the  coal  beds,  preferably  by  numbers  indicating 
feet  and  inches,  the  other  material  being  symbolized  and  the  symbols 
explained  graphically,  as  shown  in  figure  4.  The  vertical  scale  should 
always  be  stated  for  the  use  of  the  draftsman.  A  bar  scale  may  be 
used  instead  of  figures  showing  the  dimensions  of  the  individual  beds. 

861754"— 40 3 


32  PKEPARATION   OF   ILLUSTRATIONS. 

IiITHOLOGIC   SYMBOLS. 

The  symbols  used  to  indicate  the  various  kinds  of  rocks  illustrated 
in  sections  and  diagrams  are  shown  in  Plate  III.  The  units  or  ele- 
ments of  these  symbols  may  be  spaced  more  openly  in  generalized  or 
diagrammatic  sections  than  in  sections  that  show  great  detail. 

Symbols  should  be  used  consistently  throughout  a  report,  smd  in 
order  to  make  them  consistent  a  set  showing  the  symbol  to  be  used 
for  each  kind  of  rock  to  be  indicated  should  be  prepared  before  the 
original  drawings  are  made.  Some  inconsistencies  may  be  unavoid- 
able on  account  of  the  small  size  of  some  areas  shown  and  the  con- 
trast needed  between  others;  but  the  deviations  from  the  set  of 
symbols  adopted  should  be  minimized. 

USE  OF  PHOTOGRAPHS  AS  ILLUSTRATIONS. 

ESSENTIAL  FEATURES. 


The  foundat^i  of  a  good  photographic  print  is  a  good  negative, 
and  the  best  priMs  for  reproduction  as  illustrations  are  those  made 
from  negatives  in  which  tli^i^|(hsaiination  is  evenly  distributed  and 
the  details  are  sharp — such  negatives  as  are  obtainable  only  by  the 
use  of  small  stops  and  correct  focusing.  A  good  print  should  not 
present  too  sharp  contrasts  between  its  dark  and  its  light  parts ;  if  it 
does,  the  printed  reproduction  will  show  a  loss  of  detail  in  both.. 
Sufficiency  of  detail  depends  largely  on  focus,  stopping  down,  and 
timing;  brilliancy  is  the  direct  result  of  ample  illumination  by  sun  or 
artificial  light,  without  which  a  photograph  will  be  dull  or  "flat"" 
and  generally  unsatisfactory  for  reproduction.  Bad  weather  may 
prevent  good  field  exposures,  yet  even  in  bad  weather  acceptable 
negatives  may  be  obtained  by  judicious  focusing,  stopping  down, 
and  timing.  If  a  negative  is  overexposed  it  may  be  full  of  detail, 
but  flat  and  too  thin  to  print  well.  If  underexposed  it  will  show  no 
details  in  its  lighter  parts  and  the  shadows  will  be  black;  and  a 
black  shadow  is  nothing  less  than  a  blemish.  Some  detail  should 
appear  in  all  shadows  and  in  the  middle  tones,  and  some  should 
appear  in  the  high  lights ;  and  a  print  in  which  these  are  evenly  de- 
veloped and  in  which  the  illumination  is  distributed  uniformly  is 
technically  perfect. 

Unfortunately  not  all  field  photographs  are  good,  so  an  author 
must  select  from  his  collection  those  which  will  make  the  best  half 
tones.  In  making  this  selection  he  should  of  course  consider,  first, 
the  scientific  value  of  the  photograxDh,  and  next,  its  pictorial  or  artistic 
quality,  which,  though  of  secondary  importance,  should  nevertheless 
be  kept  in  mind.  A  feature  worthy  of  illustration  deserves  good  pic- 
torial expression;  if  it  is  of  superior  scientific  interest  it  should  not 
be  represented  by  an  inferior  photograph.     Fortunately,  a  good, 


PREPARATION  OF  ILLUSTRATIONS     PLATE    III 


".-ft-: 

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® 


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1  i'Mj 
I'll 

) '  /  1  1  1  1  1 

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il'l; 

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15 


Sandy  limestone 


Massively  bedded  limestone 


Calcareous  shale  or 
shaly  llmestOTie 


16 


26 


I.I       .       I       .  ~r- 


I  I   , — r" 


II  I      ,  "^~ 


Thin-bedded  limestone 


a        Shale        b 


Sandy  shale 


Schist 


Contorted  schist 


II 


■vii:^ji 


■II  ^^ 

\\„ 

«■•'■ 

\<  //ll 
(1  '-■■■^■ 

// "' 

*  ''^ 

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% 

' 

'  "a"^ 

Massive  igneous  rock 


Massive  igneous  rock 


Massive  igneous  rock 


67 


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r68) 


#*;?;>')»  Hf  if      * 
»      if     if.      M       *      i(      * 

if    if    >!■    it:    ^    ^    :^ 

K    if    ^    if    >(    /f    * 


Massive  igneous  rock 


Massive  igneous  rock 


a   Brecciated  rock   6 
(sedimentary  and  igneous) 


Bedrock 
sind  not  indicated) 


TFERENT  KINDS  OF  ROCK 


861754  O  -  49  (Face  p.  32) 


■'•/."  Tt^^T. 


SURFIGIAL 

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kos°{f. 


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-ST 


SEDIMENTARY 


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MET  AMORPHIC 


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UTHOLOGIf  SYMBOLS  t'SKD   IN   STKUCTURE  AND  COLUMNAR  SECTIONS  TO   REPRESENT  DIFFERENT  KINDS  OF  ROCK 


PREPARATION  OF  ILLUSTRATIONS.  33 

accurate  drawing  may  be  made  from  a  poor  photograph,  and  a  photo- 
graphic view  that  has  only  minor  defects  can  be  successfully  re- 
touched. Photographs  that  need  much  retouching  should  generally 
be  larger  than  publication  size,  for  the  effects  of  retouching — brush 
marks,  etc. — will  be  softened  by  reduction.  Photographs  that  need 
only  slight  retouching  need  not  be  larger  than  publication  size.  A 
photogi'aph  can  rarely  be  satisfactorily  enlarged  in  reproduction 
unless  it  is  sharp  in  detail  and  requires  no  retouching. 

Unmounted  prints  are  always  preferable  for  use  in  making  illustra- 
tions. A  group  that  is  to  form  a  single  plate  should  be  placed  in  an 
envelope  bearing  the  number  of  the  plate  and  its  title,  and  each  print 
of  the  group  should  bear  a  corresponding  number,  written  in  pencil 
on  its  back.  The  envelope  will  protect  the  prints  and  keep  them 
together,  and  the  nmnbers  will  identify  them.  Bed  ink  should  not  be 
used  to  mark  photographs,  as  it  is  likely  to  penetrate  the  coating  or 
even  the  fiber  of  the  paper,  so  that  it  can  not  be  erased. 

If  a  print  is  of  doubtful  quality  two  copies  of  it  should  be  sub- 
mitted— one  glazed,  the  other  having  a  dead  finish  or  "mat"  sur- 
face, which  is  generally  preferable  if  the  print  must  be  considerably 
retouched.  The  best  prints  for  use  as  illustrations  are  those  made  on 
"  regular  "  or  "  special "  semimat  velox  and  glossy  haloid  papers.  The 
author  should  indicate  prints  that  may  be  grouped  together  according 
to  their  relation  geographically  or  by  subject.  Generally  two  half 
tones  will  be  combined  on  a  page,  and  the  list  of  illustrations  should 
be  prepared  accordingly. 

With  slight  trimming  and  reduction,  three  photographs  measuring 
3^  by  5|  inches  may  be  made  up  one  above  the  other  to  form  a  full- 
page  octavo  plate.  Four  photogi-aphs  in  which  the  longer  dimen- 
sions represent  vertical  distances  may  sometimes  be  used  if  they  are 
placed  sidewise  on  the  page,  with  side  titles. 

Some  photogi-aphs  may  be  reduced  to  the  width  of  a  page  by 
trimming  instead  of  by  photogi*aphic  reduction,  which  may  involve 
loss  of  detail.  The  author  should  clearly  indicate  the  extent  of  such 
trimming  as  they  may  bear  without  loss  of  essential  details.  The 
trimming  is  best  done  during  the  final  preparation.  A  line  should 
not  be  drawn  across  a  photograph  to  mark  such  trimming,  but 
the  position  of  the  line  or  lines  should  be  indicated  either  on  tem- 
porary mounts,  on  the  backs  of  the  prints,  or  by  a  statement,  such 
as  "  One  inch  may  be  cut  off  on  right,  one-fourth  inch  on  left,  andi 
one-half  inch  at  bottom." 

COPYRIGHTED  PHOTOGRAPHS. 

Section  4965  (ch.  3,  title  60)  of  the  Revised  Statutes,  amended  by 
act  of  March  2,  1895  (Stat.  L.,  vol.  28,  p.  965),  provides  that  no 
copyrighted  photograph  may  be  used  without  the  consent  of  th© 


34  PREPAEATION  OF  TLLUSTEATIONS. 

proprietor  of  the  copyright  in  writing  signed  in  the  presence  of 
two  witnesses.  A  penalt}'^  of  $1  is  imposed  for  every  sheet  on  which 
such  a  photogi'aph  is  reproduced  without  consent,  "  either  printing, 
printed,  copied,  published,  imported,  or  exposed  for  sale."  An 
author  should  therefore  obtain  the  written  consent  of  the  owner  of 
a  copyrighted  photograph  to  use  it,  and  the  letter  giving  this  consent 
should  be  submitted  with  the  illustration. 

SOUKCES  OF  PHOTOGEAPHS. 

Every  photograph  submitted  with  a  manuscript  should  bear  a 
memorandum  giving  the  name  of  the  photographer  or  the  owner  of  the 
negative.  If  the  negative  is  in  the  Survey's  collection  that  fact 
should  be  stated,  as  "  Neg.  Keith  318."  The  Survey  receives  many 
requests  for  copies  of  photographs  that  have  been  reproduced  as 
illustrations  in  its  publications,  and  replies  to  these  requests  will  be 
facilitated  if  the  Survey's  number  or  the  source  of  each  photogi^aph 
presented  for  use  as  an  illustration  is  stated  as  above  on  the  photo- 
graph. 

LENDING  ORIGINAL  PHOTOGRAPHS  AND  DRAWINGS. 

A  photograph  that  has  been  used  in  making  a  half-tone  cut  for  a 
Survey  report  can  not  be  lent,  but  if  the  negative  is  on  file  a  print 
can  be  furnished  at  cost ;  and  a  Survey  drawing  that  is  well  preserved 
can  be  photogi-aphed  and  a  print  furnished,  also  at  cost.  Requests 
for  such  prints  should  be  addressed  to  the  Director. 

UNPUBLISHED   PHOTOGRAPHS. 

The  Survey  can  not  issue  a  copy  of  an  unpublished  photograph 
except  upon  the  written  approval  or  requisition  of  the  person  under 
whose  name  the  negative  is  filed.  This  requirement  does  not  apply 
to  a  print  needed  for  official  use,  nor  to  a  print  made  from  an  old 
negative  reserved  under  the  name  of  any  present  member  of  the 
Survey  or  from  a  negative  that  has  been  released  by  the  person 
under  whose  name  it  is  filed. 

Authors  using  Survey  photographs  in  unofficial  publications  are 
requested  to  aclniowledge  the  source  of  the  photogi-aph  by  adding  to 
the  printed  title  such  a  statement  as  "  Photograph  by  U.  S.  Geological 
Survey  (David  T^^lite)." 

SPECIMENS. 
GENERAL  REQUIREMENTS. 

Specimens  other  than  fossils  that  are  to  be  illustrated  in  a  report 
should  be  photographed  before  they  are  submitted,  but  the  requisi- 
tion for  the  photographs  should  be  initialed  by  the  chief  illustrator, 
who  will  indicate  the  kinds  of  prints  needed.  Duplicate  photograplis 
of  the  specimens  should  be  made  up  into  temporary  plates  by  the 


PREPAEATION  OF  ILLUSTRATIONS.  35 

author  and  submitted  with  his  other  illustrations,  the  specimens  be- 
ing retained  subject  to  call,  if  needed,  when  the  illustrations  are 
finally  prepared.  Should  a  colored  illustration  of  a  specimen  be 
needed,  however,  the  specimen  must  be  submitted  with  the  report, 
and  a  different  kind  of  print,  preferably  one  made  on  platinum  or 
other  special  paper,  will  be  obtained  by  the  section  of  illustrations. 

BORROWED  AND  FRAGILE  SPECIMENS. 

In  submitting  specimens  to  be  illustrated  an  author  should  call 
attention  to  those  that  have  been  borrowed  and  to  those  that  are 
fragile.  Borrowed  specimens  will  receive  first  attention,  so  that  they 
may  be  returned  promptly. 

TRANSMITTAL  OF  PALEONTOLOGIC  SPECIMENS. 

All  requests  for  paleontologic  illustrations  should  be  addressed  to 
the  Director.  The  letter  of  transmittal  should  state  the  title  of  the 
paper,  the  form  of  publication  desired  (bulletin,  professional  paper, 
or  monograph) ,  and  the  status  of  the  manuscript,  whether  completed 
or  in  preparation.  If  the  paper  is  unfinished  an  estimate  of  the 
number  of  illustrations  required  should  be  given,  and  the  special  rea- 
sons for  prompt  preparation  should  be  fully  stated.  A  letter  trans- 
mitting a  second  or  third  lot  of  fossils  should  refer  to  the  preceding 
lot  or  lots  if  all  the  fossils  are  to  be  used  in  illustrating  the  same 
paper. 

Fossils  that  are  to  be  drawn  should  be  sent  directly  to  the  section 
of  illustrations,  but  those  that  are  to  be  photographed  and  require 
unusual  posing  or  that  are  extremely  delicate  and  valuable  may  be 
sent  directly  to  the  photographic  laboratory  to  avoid  repeated  han- 
dling. Each  specimen  or,  if  it  is  very  small,  each  box  or  bottle  con- 
taining a  specimen  should  be  numbered,  and  each  lot  should  be  accom- 
panied by  a  list  giving  their  names  and  numbers.  Full  instructions 
as  to  size  of  reproduction,  together  with  sketches  showing  the  point 
of  view  preferred  and  any  special  features  to  be  displayed  should  also 
be  submitted.  All  specimens  that  show  strong  colors  and  all  groups 
of  specimens  that  are  not  uniform  in  color  will  be  coated  by  holding 
them  in  the  vapor  of  ammonium  chloride  unless  directions  to  the 
contrary  are  given  by  the  author  of  the  paper.  As  it  may  not  be 
desirable  to  apply  this  process  to  soft  or  fragile  specimens  or  to 
specimens  that  have  been  borrowed  an  author  should  indicate  any 
specimens  that  may  not  be  so  treated.  Specimens  whose  color  aids 
in  revealing  detail  are  not  so  coated.  If  any  features  of  a  specimen 
are  unusual  that  fact  should  be  stated  so  that  the  photographer  and 
the  retoucher  may  perform  their  work  according  to  the  requirements. 


36  PREPARATION   OF   ILLUSTRATIONS. 

MAKING  UP  PLATES. 

Two  or  more  illustrations  may  be  combined  to  fo/m  one  plate  in 
order  to  permit  easy  and  close  comparison  as  well  as  for  economy,  for 
if  a  particular  illustration  is  too  small  to  make  a  full  plate  and  is 
not  suitable  for  enlargement  other  illustrations  tha^.  are  closely  related 
to  it  may  be  put  on  the  same  plate.  The  size  of  che  printed  page  as 
given  in  the  table  on  page  11  will  determine  the  size  of  the  plate. 

In  making  up  plates  composed  of  a  number  of  figures  the  author 
should  endeavor  to  group  related  figures  together  and  at  the  same 
time  to  observe  proper  regard  for  artistic  effect,  but  as  figures  vary  in 
size  and  shape  a  grouping  according  to  relations  may  not  be  possible 
in  some  plates.  If  related  figures  can  not  be  kept  together  the  larger 
and  darker  figures  should  be  placed  in  the  lower  part  of  the  plate 
and  the  smaller  and  lighter  above.  If  a  plate  consists  of  one  large 
figure  and  several  smaller  ones  the  large  figure  should  be  placed  below 
and  the  smaller  figures  above. 

A  number  designating  a  figure  should  be  placed  immediately  below 
the  figure,  and  a  series  of  such  numbers  should  preferably  begin  with 
1  in  the  upper  left  corner  and  continue  consecutively  across  and 
down  through  the  plate.  This  arrangement  is  not  always  possible, 
however,  on  account  of  variations  in  the  size  of  figures. 

As  drawings  of  fossils  or  other  specimens  are  prepared  separately 
and  grouped  into  plates,  and  as  most  paleontologists  make  up  their 
own  plates,  each  in  his  own  wr.y,  there  is  naturally  great  dissimilarity 
in  methods  and  in  results.  Ordinary  white  or  light-gray  cardboard 
should  be  used,  and  the  figures  that  are  to  make  up  a  plate  should  be 
arranged  as  stated  above  but  not  securely  pasted  luitil  the  grouping 
is  satisfactory.  In  trimming  each  drawing  or  photogi*aph  the  author 
should  be  careful  to  leave  room  at  its  lower  edge  for  the  number. 
Small  drawings  or  photographs,  such  as  paleontologists  use,  when 
pasted  on  bristol  board  or  other  board  faced  with  tough  paper  are 
difficult  or  impossible  to  remove  without  injury  if  they  have  to  be 
remounted;  figures  pasted  on  ordinary  white  or  gray  cardboard  can 
be  removed  without  difficulty.  Each  plate  should  be  made  up  in  a 
size  to  fit  the  volume  or  in  its  correct  proportion  to  a  page  in  the 
volume  in  which  it  is  to  be  used  (see  table  on  p.  11),  and  each  figure 
should  be  properly  oriented — ^that  is,  all  vertical  lines,  or  the  vertical 
axis  of  each  specimen,  should  be  parallel  with  the  sides  of  the  plate. 
When  the  figures  are  being  mounted  care  should  be  taken  that  thf» 
mucilage  or  paste  does  not  exude  under  pressure  and  cover  any  part 
of  the  drawing  or  photograph.  The  same  attention  should  be  given 
to  pasting  on  numbers.  Inattention  to  these  details  ma}'  produce 
Jesuits  that  will  affect  the  reproduction  of  the  plates. 


PREPAEATION   OF  ILLTJSTRATIONS,  37 

Ordinary  mucilage  may  be  used  for  mounting  drawings  and  photo- 
graphs, but  photo  paste  gives  good  results  and  is  perhaps  cleaner  to 
handle.  Dry-mounting  tissue  is  well  adapted  to  mounting  single 
illustrations  but  not  groups  of  figures.  Liquid  rubber  is  sometimes 
used,  but  it  is  not  suitable  for  mounting  small  figures,  such  as  draw- 
ings and  photographs  of  fossils.  It  can  be  used  satisfactorily  for 
mounting  temporary  plates  and  for  mounting  photographs  in  albums 
and  on  large  cards  for  study  or  exhibition ;  but  it  has  not  proved  to 
be  a  permanent  adhesive.  Its  special  merit  is  that  it  does  not  cause 
either  the  photograph  or  the  mounting  sheet  to  warp.  It  is  applied 
by  spreading  it  evenly  over  the  back  of  the  photograph  with  the 
fingers.  The  superfluous  rubber  can  easily  be  removed  from  the 
hands  and  from  the  cards  or  sheets  when  it  is  dry.  Anything  mounted 
with  liquid  rubber  can  be  easily  removed. 

If  a  plate  is  to  be  made  up  of  a  small  numl^er  of  figures  that  require 
different  reductions,  the  author,  instead  of  mounting  or  pasting  the 
-separate  figures  on  one  card  in  the  manner  already  indicated,  may 
draw  a  rectangle  of  the  size  of  the  printed  plate  and  sketch  within  it 
the  several  figures  in  their  respective  sizes  and  positions.  These 
"  dummy  "  plates  or  layouts  should  be  numbered  as  plates,  and  they 
may  bear  captions  and  titles.  The  photographs  or  drawings  repre- 
sented by  the  sketches  should  then  be  numbered  to  identify  them  with 
the  sketches  on  the  dummy  plate,  and  those  that  pertain  to  each  plate 
should  be  inclosed  in  an  envelope  attached  to  the  dummy  plate.  A 
plate  made  up  in  this  manner  will  meet  every  requirement  of  the 
photo-engraver  or  lithographer. 

If  a  paleontologist  so  desires,  his  plates  can  be  permanently  made 
up  after  he  has  transmitted  his  material,  but  he  should  always  sub- 
mit a  tentative  arrangement, 

REUSE    OF   ILLUSTRATIONS. 

If  an  author  desires  to  use  in  modified  fonn  an  illustration  already 
published,  whether  by  the  Geological  Survey  or  by  an  outside  pub- 
lisher, he  should  furnish  a  print  or  tracing  of  the  illustration  show- 
ing the  changes  desired.  If  the  illustration  is  not  to  be  modified  he 
need  only  give  the  title  of  the  volume  in  which  it  was  used,  with  the 
number  of  the  page,  figure,  or  plate,  and  he  need  not  make  a  sketch 
of  the  illustration  or  furnish  a  dummy ;  but  its  title  should  be  quoted 
and  proper  reference  should  be  given  in  the  list  of  illustrations.  Due 
credit  should  be  given  to  the  author  or  publisher. 

The  original  cuts  of  illustrations  will  be  kept  for  one  year  after  the 
report  for  which  they  were  made  has  been  published,  and  authors  of 
later  reports  may  and  should  reuse,  whenever  practicable,  any  such  cut 
that  will  serve  as  an  illusti^ation.    In  the  author's  list  of  illustrations 


38  PREPAKATION  OF  ILLUSTRATIONS. 

such  a  cut  should  be  referred  to  by  its  number  as  plate  or  figure  and 
the  volume  in  which  it  was  first  used. 

An  electrotype  of  any  cut  on  hand  will  be  furnished  for  use  in  pub- 
lications other  than  those  of  the  Geological  Survey  at  the  cost  of 
maldng,  which  is  3|  to  5|  cents  a  square  inch  of  printing  surface. 
The  minimum  charge  for  a  single  electrotype  ranges  from  45  to  60 
cents. 

APPROVAL  OF  FINISHED  ILLUSTRATIONS. 

After  the  drawings  for  a  report  have  been  prepared  they  will  be 
submitted  to  the  author  or  to  the  chief  of  his  branch  or  division  for 
examination.  The  finished  drawings  will  be  accompanied  by  the 
"  originals,"  with  which  the  author  should  carefully  and  thoroughly 
compare  them.  After  making  a  thorough  comparison  he  should  mark 
lightly  with  a  pencil,  on  the  finished  drawings,  all  necessary  correc- 
tions, or  indicate  his  approval  subject  to  such  corrections  and  addi- 
tions as  may  be  required.  He  should  verify  all  type  matter  and  other 
lettering  and  assure  himself  that  no  mistakes  have  been  made  in 
grouping  the  photographs  into  plates,  especialW  such  as  have  been 
regrouped  since  they  left  his  hands.  The  author's  list  of  illustra- 
tions will  be  submitted  with  the  new  drawings  for  this  purpose. 

REVISION  OF  ILLUSTRATIONS. 

All  illustrations  receive  editorial  revision  before  they  are  sent  to 
the  engravers.  After  they  are  drawn  they  are  examined  with  refer- 
ence to  their  scientific  features  and  their  accuracy,  and  then  in  turn 
with  reference  to  the  correctness  of  geologic  names  and  geographic 
names  and  to  errors  in  statement  and  in  spelling.  Each  illustration 
thus,  before  it  is  completed,  receives  critical  examination  by  persons 
qualified  in  particular  kinds  of  work  to  detect  errors  or  omissions. 

SUBMITTAL  OF  PROOFS. 

The  first  proofs  of  all  illustrations  are  submitted  to  an  author 
when  he  is  within  reach,  but  if  he  is  in  the  field  and  the  transmittal 
of  the  proofs  to  him  is  likely  to  cause  too  much  delay  they  are  sub- 
mitted to  the  chief  of  the  branch  or  division  in  which  the  report  was 
prepared.  Second  proofs  of  the  more  complicated  illustrations, 
particularly  geologic  maps,  may  be  submitted.  An  author's  exami- 
nation should  be  confined  principally  to  the  revision  of  the  scientific 
features  of  his  illustrations,  but  suggestions  as  to  general  elFective- 
ness  are  always  acceptable. 

The  process  to  be  used  in  engraving  each  illustration  is  stamped  in 
its  lower  left  comer.  In  examining  proofs  an  author  should  note 
the  following  facts : 

1.  Changes  can  not  be  made  in  zinc  etchings  except  by  eliminating 
parts,  cutting  a^way  defects,  and  connecting  lines.    If  additions  are 


PREPARATION  OF  ILLUSTRATIONS.  39 

required  reengraving  is  generally  necessary,  and  reengraving  should 
preferably  be  avoided. 

2.  Changes  can  be  made  in  half-tone  plates  only  by  reetching  or 
by  tooling  parts  to  make  them  lighter  and  by  burnishing  parts  to 
make  them  darker.  If  the  proof  shows  a  general  loss  of  detail  the 
fault  may  lie  either  in  the  proving  of  the  cut  or  in  the  reproduction. 
If  it  is  in  the  reproduction  it  can  not  be  remedied  without  reengrav- 
ing. A  slight  loss  of  detail  may  be  expected  in  all  half  tones,  espe- 
cially in  those  that  are  smaller  than  the  copy  submitted. 

3.  Minor  changes  can  be  made  in  photolithographs  and  chromo- 
lithographs, but  changes  can  not  be  made  twice  in  one  place  without 
danger  of  affecting  the  printing.  It  is  customary  to  approve  all 
lithographic  proofs  subject  to  the  corrections  indicated,  the  printed 
edition  being  examined  and  compared,  but  if  the  changes  are  numer- 
ous and  radical  second  proofs  may  be  required.  Second  combined 
proofs  of  chromolithographs  are  very  expensive.     (See  p.  89.) 

PROOF    READING   ILLUSTRATIONS. 

An  author  should  examine  the  proofs  of  his  illustrations  closely 
and  should  compare  them  carefully  with  the  original  drawings. 
A  mere  cursory  examination  may  fail  to  detect  errors  that  have  not 
been  caught  by  the  regular  proof  reader.  Every  correction  desired 
should  be  clearly  indicated  with  pen  and  ink  in  the  body  of  the  proof 
and  inclosed  in  a  loop  from  which  a  line  should  be  carried  to  a 
marginal  note  or  comment,  but  if  the  time  available  is  short  a  pencil 
may  be  used.  In  correcting  type  matter  or  lettering  (such  as  that 
in  a  geologic  legend  or  explanation)  the  ordinary  proof  reader's 
marks  should  be  used.  The  author  or  the  person  examining  the  proofs 
should  initial  each  one  at  the  place  indicated  by  a  rubber  stamp. 

Proofs  should  be  held  only  long  enough  to  examine  them  properly 
and  to  compare  them  with  the  original  illustrations,  for  a  time  limit 
is  fixed  in  each  contract  for  engraving,  and  if  the  author  holds  proofs 
beyond  a  reasonable  time  he  causes  a  delay  in  the  fulfillment  of  the 
contract. 

As  the  illustrations  for  many  reports  contain  important  data  that 
will  be  discussed  in  the  text,  proofs  of  illustrations  can  not  be  sup- 
plied to  any  applicant  without  consent  from  the  Director's  office. 

GENERAL  CONSIDERATIONS. 

The  following  requirements  are  essential  to  obtain  good  original 
illustrations : 

1.  The  material  selected  should  be  pertinent  and  expressive;  it 
should  have  the  qualities  essential  to  good  illustrations. 


40  PREPARATION    OF   ILLUSTRATIONS. 

2.  The  character  of  the  report  and  the  size  of  the  illustrations 
should  be  kept  clearly  in  mind.  If  the  report  is  preliminary  or 
ephemeral  the  illustrations  should  be  simple  and  inexpensive.  If 
the  report  represents  the  sum  of  knowledge  on  the  subject  treated  or 
the  last  word  on  some  particular  area  the  illustrations  may  be  more 
elaborate.  The  character  of  a  report  generally  determines  the  form 
of  publication,  which,  in  turn,  determines  the  size  of  the  pages  and 
the  size  of  the  plates  and  figures.  Every  sketch  made  should  be 
larger  than  publication  size — preferably  twice  publication  size — 
whether  it  is  a  simple  diagram  or  a  base  map. 

3.  The  kind  of  reproduction  that  is  apparently  needed  should  be 
fully  considered,  for  it  should  have  some  relation  to  the  kind  of 
report.  The  illustrations  for  short-lived  reports  are  reproduced 
by  the  cheaper  processes.  Those  for  hurried  reports  are  reproduced 
by  processes  that  can  be  worked  quickly,  but  no  process  should  be 
considered  that  will  not  give  a  clear  reproduction  of  essential  details. 

4.  Clearness  of  preparation  of  original  matter  is  invariably  essen- 
tial. An  author  should  not  expect  the  draftsmen  or  the  editors  to 
supply  missing  links.  Each  original  should  be  complete  and  should 
be  so  made  that  it  can  be  understood  and  followed  without  question. 
Changes  made  in  the  finished  drawings  or  on  proof  sheets  are  ex- 
pensive and  delay  publication. 


PART  II.    PREPARATION  BY  DRAFTSMEN. 
GENERAL  DIRECTIONS. 

The  work  of  preparing  illustrations  such  as  are  used  in  the  reports 
of  the  Geological  Survey  is  essentially  that  of  making  finished  draw- 
ings from  more  or  less  crude  and  imperfect  material  furnished  by 
authors  to  illustrate  certain  features  or  phenomena  discussed  in  their 
manuscripts.  Each  finished  drawing  must  be  so  prepared  that  it  can 
be  reproduced  in  multiple  by  one  of  several  processes  of  engraving. 
The  author's  sketches  and  other  material  are  commonly  called  "  orig- 
inals " ;  the  finished  illustrations  are  known  by  the  engravers  as 
"  copy."  Though  most  engraver's  copy  consists  of  more  or  less 
elaborate  drawings  that  are  to  be  reproduced  in  facsimile  by  "  di- 
rect "  processes  without  the  interposition  of  handwork,  some  of  it 
consists  of  more  roughly  prepared  copy  which  is  accurate  in  state- 
ment but  requires  complete  manual  or  "indirect"  reproduction. 
The  direct  processes  in  use  are  zinc  etching,  half-tone  engraving, 
photolithography,  three-color  half  tone,  photogravure,  and  photo- 
gelatin.  The  manual  or  indirect  processes  are  wax  engraving,  wood 
engraving,  engraving  on  copper  and  on  stone,  plain  lithography,  and 
chromolithography.     These  processes  are  described  on  pages  72-90. 

Part  I  of  this  pamphlet  contains  some  matter  that  is  pertinent  to 
final  preparation  and  should  be  consulted  by  draftsmen. 

To  prepare  a  drawing  that  will  be  in  every  way  suitable  for  repro- 
duction usually  requires  experience  of  a  kind  not  acquired  in  many 
other  kinds  of  drafting,  such  as  preparing  engineers'  or  architects' 
drawings,  because  the  drawings  themselves  or  blue  prints  made  di- 
rectly from  them  are  the  things  the  engineer  or  the  architect  desires. 
Drawings  prepared  for  reproduction  are  generally  made  larger  than 
publication  size,  and  it  is  therefore  necessary  to  gage  each  line, 
letter,  or  feature  for  a  definite  reduction.  Engineers'  and  archi- 
tects' drawings  generally  do  not  require  preparation  for  reproduction 
by  any  process,  but  in  preparing  illustrations  for  the  reports  of  the 
Geological  Survey  reproduction  must  be  fully  considered  at  every 
step,  and  each  drawing  must  be  made  according  to  the  requirements  of 
a  certain  selected  process  and  gaged  for  a  certain  reduction.  The 
draftsman  should  therefore  know  how  to  plan  each  drawing  step 
by  step  for  an  engraved  cut,  a  lithograph,  a  text  figure,  or  a 
plate,  always  with  a  definite  result  in  view.  He  should  be  familiar 
with  processes  of  engraving  and  should  know  the  special  requirements 

41 


42 


PREPARATION  OF  ILLUSTRATIONS. 


of  each  process,  and  he  should  be  able  to  prepare  drawings  for  any 
sj)ecLfied  reduction  in  a  way  to  insure  good,  legible  reproduction. 

The  geologic  draftsman  should  read  and  study  such  textbooks  of 
geology  as  those  of  Dana  and  Geikie  and  should  familiarize  himself 
with  structural  geology,  the  geologic  time  divisions,  and  geologic 
nomenclature.  He  should  be  able  to  prepare  a  simple,  effective  illus- 
tration from  complicated  rough  originals  and  to  supply  minor  miss- 
ing essential  parts  or  features.  To  perform  his  work  successfully 
he  must  possess  mechanical  skill  and  some  artistic  taste,  as  well  as 
good  eyesight  and  gi'eat  patience. 


INSTRUMENTS. 

The  following  list  of  draftsmen's  instruments  is  practically  com- 
plete. Those  which  are  considered  indispensable  are  marked  by 
asterisks;  the  others  may  be  used  according  to  individual  preference. 
The  same  kind  of  instrument,  may  be  duplicated  in  different  sizes 
according  to  the  variation  in  the  demands  of  the  work. 


Air  brush  and  connections. 

Beam  compass. 

Bow  pen,  drop  spring. 
*Bow  pen,  steel  spring. 

Bow  pencil,  steel  spring. 
*Brushes,   red  sable. 

China  saucers. 
*Color  box. 
*Compass,  pen  and  pencil  points. 

Crayons,  assorted  colors. 

Curve  rule,  adjustable. 
♦Dividers,  plain. 
♦Dividers,  proportional. 

Dividers,  steel  spring. 

Drawing  boards,  several  sizes. 

Eraser,  glass. 
♦Eraser,  rubber,  hard. 
♦Eraser,  rubber,  soft. 
♦Eraser,  steel. 

lOrasing  shield. 
♦French  curves,  xylonite. 

Miscroscope,  low  power  and  lenses 

Palette  knife. 

Pantograph. 

Pens,  double-pointed. 
♦Pens,  Gillott's,  Nos.  170,  290,  291. 


Pens,  K.  &  E.,  drawing.  No.  3202. 

Pens,  Payzant's,  1   set. 
^Pencils,  best  quality,  graded  leads. 
♦Protractor. 

Railroad  curves,  pearwood,  1  set. 

Railroad  pen. 
♦Railroad  pencil. 

Reading  glass. 
♦Reducing  glass. 
♦Ruling  pen. 

Scale,  boxwood,  12  inches  long,  with 
divisions  of  millimeters  and  inches. 

Scales,  boxwood,  triangular. 

Section  liner  (parallel  iniling  device). 

Straightedge,  steel,  24  inches. 

Straightedge,    steel,   36   inches,   with 
divisions  for  hundredths  of  an  inch 
and  millimeters. 
*  Straightedge,  wood,  24  inches. 

Swivel  or  curve  pen. 

Thumb  tacks. 

Tracing  point,  steel. 
♦Triangle,  45°. 
♦Triangle,  60°. 

*T  square,  pearwood.  xylonite  edge. 
*T\veezers,  dentist's. 


CLASSIFICATION  OF  MATERIAL. 

The  draftsman  handling  the  drawings  and  other  original  material 
submitted  by  the  author  of  a  report  for  its  illustration  should  first 
group  them,  as  far  as  possible,  into  kinds  or  classes,  in  order  that 


PREPAKATION   OF  ILLUSTRATIONS.  43^ 

he  may  decide  how  each  illustration  should  be  prepared  (1)  to  ex- 
press most  effectively  the  author's  purpose,  (2)  to  insure  reasonable 
economy  in  preparation  and  in  reproduction,  and  (3)  to  meet  the  re- 
quirements of  the  processes  of  reproduction  selected.  All  similar 
illustrations  for  one  publication  should  be  prepared  in  the  same  gen- 
eral style.  In  a  series  of  geologic  sections,  for  example,  the  same 
lithologic  symbols  should  be  used  throughout  for  the  same  kinds  of 
rocks.  The  titles,  explanations,  and  captions  of  the  maps  should  also 
agree  with  one  another  in  general  style  and  in  details  of  workmanship. 

The  draftsman  should  determine  in  advance  the  reduction  for  each 
drawing  or  for  each  group  of  drawings,  in  order  that  he  may  use 
the  same  size  of  letters  or  the  same  kinds  of  type  for  the  lettering  on 
a  series  of  drawings  that  require  the  same  reduction.  The  reduction 
should  preferably  be  marked  in  fractions  (as  "3/2  off,"  "  ^4  off  "  or 
"  reduce  i/^,"  "  reduce  ^/4  ") ,  and  the  choice  of  the  same  reduction  for  a 
group  of  drawings  will  not  only  insure  greater  uniformity  in  the 
drafting  and  in  the  reproduction  but  will  permit  the  drawings  to  be 
reproduced  more  economically,  for  the  engraver  can  photograph, them 
in  groups  instead  of  each  one  separately. 

The  draftsman  should  therefore  note  and  consider  (1)  the  special 
features  shown  in  the  author's  originals;  (2)  whether  or  not  these 
features  have  been  plainly  indicated  and  whether  the  originals  are 
complete;  (3)  the  size  of  the  printed  page  of  the  volume  in  which 
the  illustrations  will  appear  and  the  reduction  required  for  each 
drawing;  and  (4)  the  process  by  which  each  drawing  should  be  re- 
produced. If  an  original  is  of  doubtful  or  uncertain  interpretation 
or  appears  to  be  incomplete  the  draftsman  should  confer  with  the 
author  of  the  paper  if  he  is  within  reach  or  should  bring  the  matter 
to  the  attention  of  the  chief  of  the  branch ;  otherwise  he  may  waste 
much  time  in  making  the  drawing. 

PREPARATION  OF  MAPS. 

PROJECTION. 

The  base  maps  furnished  by  authors  (see  pp.  13-14)  are  prepared 
in  many  different  ways  and  in  different  degrees  of  refinement  and  of 
crudity,  but  the  work  of  redrawing  them  for  reproduction  involves 
well-established  and  generally  uniform  principles.  All  maps  except 
those  of  very  extensive  areas  should  be  based  on  a  map  projection 
which  will  show  with  a  minimum  of  distortion  the  effect  of  the  curva- 
ture of  the  earth.  The  polyconic  projection  (see  fig.  5)  is  used  for 
most  Government  maps.  In  this  projection  the  central  meridian  is  a 
straight  vertical  line,  and  each  parallel  of  latitude  is  developed  inde- 
pendently of  the  others.    The  mathematical  elements  of  map  projec- 


44 


PREPARATION    OF   n^LUSTRATIONS. 


tion  are  given  in  tables  published  by  the  Geological  Survey^  and  the 
Coast  and  Geodetic  Survey.^  Figure  5,  however,  illustrates  the  me- 
chanical or  constructional  features  of  the  polyconic  projection  and  if 
used  in  connection  with  the  published  tables  will  probably  be  a  suffi- 
cient guide  for  projecting  a  map  on  any  desired  scale. 

In  projecting  a  map  first  select  a  convenient  measuring  scale  for 
setting  off  the  dimensions  given  in  the  tables,  or  if  no  scale  is  at 
hand  one  may  be  constructed.  Measuring  scales  are  made,  however, 
bearing  divisions  for  miles  and  kilometers  and  finer  subdivisions  of 
5  to  100  parts.  They  include  the  ratios  of  1 :  31,250,  1 :  31,G80,  1 :  48,- 
000,  1 :  62,500,  1 :  63,360,  1 :  125,000,  1 :  250,000,  1 :  500,000,  1 : 1,000,000, 
and  others.    On  a  map  drawn  on  the  scale  of  1  to  63,360,  for  example, 


Degrees  from  central  meridian- - 0 

Distance  in  meters  from  central  meridian 0 


2° 

:82,568 


4" 
365,05* 


6° 

547,412 


8° 
7Z9,542 


10° 
911,379 


Figure  5. — Diagram  illustrating  method  of  projecting  a  map. 


1  inch  would  represent  1  mile ;  on  a  map  drawn  on  the  scale  of  1  to 
1,000,000, 1  millimeter  would  represent  1  kilometer,  and  so  on.  It  will 
be  seen  that  the  use  of  a  scale  that  shows  in  ratios,  such  as  those  just 
given,  the  actual  distance  on  the  ground  as  compared  with  the  unit 
representing  the  same  distance  on  the  map  will  reduce  the  possibility 
of  error. 

The  method  of  projecting  a  map,  illustrated  in  the  accompany- 
ing diagram  (fig.  5),  is  as  follows:  First  draw  a  straight  vertical  line 
(A)  through  the  middle  of  the  sheet  to  represent  the  central  meridian 

^  Gajinett,  S.  S.,  Geographic  tables  and  formulas,  4th  ed.  :  U.  S.  Geol.  Survey  Bull. 
650,  1916.  See  also  Gannett,  Henry,  Manual  of  topographic  methods :  U.  S.  Geol.  Sur- 
vey Bull.  .107,  pp.  85-86,  1006. 

■*  Methods  and  r<'sults :  Tables  for  the  projection  of  maps  and  polyconic  development ; 
Appendix  No.  6,  Report  for  1884 ;  Tables  for  a  polyconic  projection  of  maps,  bafied  upon 
Clarke's  reference  spheroid  of  1886  ;  3d  ed.,  1910. 


PREPARATION   OF  ILLUSTRATIOITS.  45 

of  the  map  and  a  line  (B)  at  the  lower  end  of  this  line  exactly  at 
right  angles  to  it  to  represent  the  bottom  of  the  map.  Then  set  off 
on  the  line  showing  the  central  meridian  the  distances  between 
parallels  given  in  Table  6  on  page  36  of  "  Geographic  tables  and 
formulas"  (Bull.  650).  It  should  be  noted  that  the  figures  in  these 
tables  give  the  distance,  in  meters  and  statute  miles,  of  1°  on  a 
meridian  measured  30'  each  way  from  a  point  where  the  meridian  is 
intersected  by  a  parallel.  The  exaot  distances  between  parallels  as 
measured  on  the  ground  are  given  in  the  Coast  and  Geodetic  Survey 
tables,  or  they  may  be  computed  from  Table  6  of  "Geographic  tables 
and  formulas  "  by  adding  the  sum  of  the  figures  given  for  any  two 
latitudes  1°  apart  and  dividing  by  2. 

The  distance  between  parallels  that  are  2°  apart,  as  shown  in  the 
diagram,  may  be  computed  from  Table  6  of  "  Geographic  tables  and 
formulas,"  as  follows: 

Meters.  Meters. 

1°    of   latitude   on   37th   parallel =100,975.1-^2=  55,4S7. 5 
1°    of  latitude   on   36th    parallel =110,956.2 

1°    of   latitude   on   35th  parallel=110,937.6-H-2=  55,468.8 

True  distance  from  35°  to  37°  latitude =221,  912.  5 

The  distances  given  in  the  diagi'am  were  obtained  by  adding  the 
figures  given  in  the  Coast  and  Geodetic  Survey  tables,  which  yield 
the  same  results.  Other  tables  in  Bulletin  650  give  the  true  distances 
in  inches  on  maps  of  certain  standard  scales. 

Through  the  points  thus  obtained  on  the  central  meridian  draw 
lines  at  right  angles  to  the  vertical  line.  Along  these  horizontal 
lines  lay  off  the  dimensions  in  the  column  headed  X,  Table  6  (pp. 
39^7)  of  "  Geographic  tables  and  formulas  "  as  required  for  each 
individual  map — in  the  diagram  every  alternate  degree.  Draw  ver- 
tical lines  at  these  points  and  set  off  the  distance  Y  in  the  same  table 
in  a  similar  manner,  and  the  points  so  found  will  be  the  points  of  in- 
tersection of  the  respective  meridians  and  parallels.  Figures  are 
given  on  the  diagram  for  the  thirty-fifth  parallel  only. 

DETAILS  OF  BASE  MAPS. 

Anyone  who  attempts  to  draw  a  base  map  must,  first  of  all,  know 
how  each  feature  or  part  of  the  map  should  be  represented.  Most  of 
the  conventional  symbols  for  features  shown  on  base  maps  are  well 
established  and  should  invariably  be  used;  for  instance,  a  line  com- 
posed of  alternate  long  and  short  dashes  (not  dashes  and  dots)  repre- 
sents a  county  boundary,  and  a  line  or  two  parallel  lines  across  which 
short  lines  are  drawn  at  regular  intervals  represents  a  railroad.  If 
he  finds  that  two  or  more  symbols  have  been  widely  used  to  represent 


46  PREPABATION  OF  ILLUSTRATIONS. 

the  same  feature  the  draftsman  should  select  the  one  that  is  best 
suited  to  the  map  in  hand.  The  correct  forms  of  the  conventional 
symbols  or  features  to  be  used  in  preparing  miscellaneous  maps  are 
shown  in  Plate  IV,  but  the  size  and  weight  of  each  line  or  symbol  must 
depend  on  the  size  and  character  of  the  map. 

TRANSFERRING  OR  COPYING. 
TEACING. 

The  oldest  method  of  transferring  a  map  or  parts  of  a  map  or 
other  drawing  to  another  sheet  is  that  of  copjdng  it  by  means  of 
tracing  paper.  This  method,  though  still  used  for  simple  work,  has 
given  way  to  quicker  and  more  effective  methods.  By  one  of  these 
methods  a  piece  of  thin,  fairly  smooth  paper  (not  necessarily  trans- 
parent) is  coated  with  graphite  by  rubbing  over  it  a  soft  pencil. 
When  the  graphite  has  been  evenly  distributed  over  it,  this  sheet  is 
laid  upon  the  drawing  paper,  coated  side  down,  the  map  or  other  sub- 
ject to  be  copied  is  laid  upon  the  graphite-coated  sheet,  and  the  two 
outer  sheets — the  drawing  paper  and  the  map — are  securely  fastened 
together.  By  a  steel  tracing  point  or  very  hard  pencil  the  lines  and 
other  details  of  the  matter  to  be  copied  are  then  firmly  and  carefully 
traced  and  thus  transferred  to  the  clean  drawing  paper  beneath. 

For  maps  that  show  several  features  in  different  colors  sheets 
rubbed  with  blue,  orange,  brown,  or  green  pencils  may  be  used,  one 
after  another,  for  tracing  each  set  of  the  features.  Red  should  not 
be  used,  as  it  is  not  easily  erased.  This  method  insures  distinctive 
lines  for  the  separate  features  and  prevents  the  confusion  that  might 
result  from  the  use  of  one  color  only.  Exact  register  of  the  features 
shown  in  the  several  colors  used  may  be  insured  by  fastening  one 
edge  of  the  drawing  to  be  copied  to  the  drawing  paper  by  mucilage 
or  thumb  tacks.  The  colored  sheets  may  then  be  slipped  in  and  out 
without  altering  the  position  of  the  lines  or  s}'mbols  for  one  set  of 
data  with  relation  to  those  for  the  others. 

In  the  final  preparation  of  a  base  map  to  be  engraved  and  printed 
in  colors — for  example,  black,  blue,  and  brown — tracings  of  the  three 
colors  appearing  on  the  original  base  should  generally  be  transferred, 
as  described  above,  to  one  sheet  of  paper  and  thus  worked  up  into 
a  three-colored  map.  It  is  usually  unnecessary  and  undesirable  to 
draw  each  color  on  a  separate  sheet.  The  preparation  of  separate 
drawings  may  facilitate  reproduction,  but  if  they  are  made  on  tracing 
cloth  the  usual  uneven  shrinking  or  stretching  of  the  cloth  may  pro- 
duce misregister  in  the  printing ;  therefore  it  is  safer  to  make  a  single 
drawing,  so  that  the  photolithographer  can  make  three  negatives  and 


PREPAKATION  OF  ILLUSTRATIONS.  47 

separate  the  colors  by  painting  out  or  "opaquing"  the  colors  not 
wanted  on  each  negative.  A  map  drawn  on  a  single  sheet  is  also 
less  bulky  and  can  therefore  be  more  conveniently  handled  and  com- 
pared with  proof. 

If  for  any  reason  separate  tracings  for  the  different  colors  to  be 
used  on  a  map  are  considered  desirable  they  should  be  made  on  linen 
cut  from  one  roll  and  in  the  same  direction  according  to  the  warp 
and  woof. 

CELLITLOID  TRANSFERRING. 

In  the  celluloid  method  of  transferring  a  map  or  parts  of  a  map 
to  paper  upon  which  a  complete  new  map  is  to  be  drawn  the  map  or 
part  of  the  map  to  be  copied  is  photographed  to  the  exact  scale  of 
the  new  drawing  and  reproduced  in  graphite  on  thin  sheets  of 
celluloid. 

The  celluloid  sheet  is  then  laid  face  down  in  the  correct  position 
on  the  drawing  paper  and  firmly  rubbed  on  the  back  with  a  steel 
burnisher,  which  makes  a  perfect  offset  of  the  map  on  the  paper. 
After  the  parts  desired  are  inked  over  the  rest  of  the  graphite  print 
is  easily  erased  with  an  ordinary  rubber. 

By  using  this  method  it  is  possible  to  get  absolute  scale  and  more 
satisfactory^  results  than  by  tracing  over  a  photographic  print  line 
for  line  or  by  using  a  pantograph. 

Requisitions  for  celluloid  prints  are  made  on  the  form  used  for 
requesting  photolithographic  work. 

SKETCHING  BY  RETICULATION. 

If  the  sheet  bearing  the  design  or  matter  to  be  copied  may  be 
marred  without  objection  it  is  ruled  lightly  into  pencil  squares  of 
equal  size.  Corresponding  squares  of  the  same  size,  larger,  or 
smaller,  according  to  the  size  of  the  new  drawing,  are  then  ruled  on 
the  drawing  paper,  and  the  work  is  sketched  square  by  square.  If 
the  original  sheet  uiaj  not  be  marred  the  same  result  can  be  obtained 
by  drawing  the  lines  on  a  transparent  oversheet.  This  method  is 
serviceable  for  enlarging  or  reducing  simple  work  that  includes  no 
great  amount  of  detail;  if  great  precision  of  detail  is  required  the 
original  should  be  enlarged  or  reduced  by  photography  or  by  the 
pantograph. 

THE  "  SHADOWLESS  DRAFTING  TABLE." 

One  of  the  most  useful  contrivances  that  has  been  made  for  tracing 

a  drawing  on  the  same  scale  is  called  by  its  manufacturers  the 
"  shadowless  drafting  table."  The  essential  features  of  this  table  are 
a  wooden  box  inclosing  strong  incandescent  lights  and  bearing  a 
ground-glass  top.    A  drawing  placed  on  the  ground  glass  can  be  so 

861754° — 49 i 


48  PREPAKATION  OF  ILLUSTRATIONS. 

illuminated  as  to  make  its  lines  conspicuous  and  readily  traceable 
even  through  relatively  thick  paper.  The  table  is  particularly  use- 
ful for  tracing  sheets  upon  which  the  lines  are  indistinct  and  would 
not  be  discernible  under  tracing  paper  with  reflected  light.  It  is  also 
useful  in  preparing  drawings  in  which  certain  features  must  register 
perfectly  over  each  other.  In  fact  any  drawing  that  does  not  require 
enlarging  or  reducing  can  be  traced  with  great  facility  by  the  use 
of  this  drafting  table,  and  it  is  particularly  useful  for  tracing  faint 
lines  on  old  and  poorly  preserved  prints  or  drawings. 

Such  a  table  has  been  installed  in  the  section  of  illustrations,  where 
it  can  be  used  by  authors  and  others. 

TOPOGRAPHIC  FEATURES. 
RELIEF. 

The  effect  of  relief  is  expressed  on  a  map  by  three  methods — by 
contours,  by  hachures,  and  by  shading.  (See  fig.  6.)  The  first 
method  does  not  give  pronounced  pictorial  expression  of  relief, 
though  it  gives  correct  shape  and  exact  jelevation ;  the  others  are  more 
pictorial,  but  they  do  not  give  exact  elevation. 

Contours. — As  contoured  maps  are  originally  prepared  from  actual 
surveys  the  draftsman  should  simply  follow  the  copy  furnished  by 
the  topographer  or  such  original  matter  as  may  be  given  to  him  for 
redrawing.  If  the  area  mapped  is  large  and  the  contours  are  close 
together  the  original  may  be  transferred  by  celluloid  tracing  (see 
p.  47),  or  it  may  be  transferred  by  tracing  with  graphite-coated 
paper  (see  p.  46).  After  the  contour  lines  have  been  transferred 
they  should  be  traced  in  ink,  in  lines  of  even  thickness,  except  those 
that  represent  certain  fixed  intervals  and  are  to  be  numbered,  which 
should  be  made  slightly  thicker.  (See  fig.  6,  A.)  In  drawing  these 
lines  some  draftsmen  use  an  ordinary  ruling  pen,  others  the  swivel 
pen ;  but  considerable  practice  is  required  in  the  use  of  either  before 
it  can  be  controlled  to  follow  precisely  the  penciled  lines.  Still 
other  draftsmen  use  the  Shepard  pen  or  an  ordinary  drawing  pen. 
The  swivel  pen,  if  expertly  handled,  produces  a  firm  and  even  line. 

Italic  numbers  should  be  used  to  indicate  the  elevation  of  a  con- 
tour and  should  be  placed  in  an  opening  in  the  line,  never  between 
lines.  Where  the  lines  run  close  together  great  care  should  be  taken 
that  they  do  not  touch  unless  the  interspaces  are  so  narrow  that  they 
must  touch  and  combine.  The  lines  should  be  firm  and  even,  and  if 
the  copy  or  original  map  shows  that  they  are  uniformly  very  close 
together  it  should  be  enlarged  before  the  tracing  is  made  in  order  to 
give  more  freedom  in  drawing;  but  if  the  enlarged  map  is  to  be 
much  reduced  care  should  be  taken  to  make  the  lines  proportionate 
to  the  reduction.    A  photo-engraving  of  a  map  on  which  the  contour 


PREPAKATIOISr   OF   ILLUSTRATIOlSrS. 


49 


lines  are  drawn  very  close  together  is  likely  to  be  unsatisfactory  be- 
cause, though  the  spaces  between  the  lines  are  reduced  in  width,  the 
lines  themselves  may  show  no  corresponding  reduction  in  thickness. 


i^.- 


c 


4». 


is- Mill 


l.\ 


ll-SV^/j  > ///> 


D 


Figure  6. — Methods  of  expressing  relief:  (A)  by  contour  lines,  (B)  by  hachures,  (C)  by 
shading  on  stipple  board,  and  (D)  by  a  brush  drawing.  Tfee  four  examples  given  rep- 
resent the  same  area.     The  drawings  were  made  twice  the  size  of  the  printed  cuts. 

Certain  contour  lines  are  commonly  accentuated  on  a  map,  gener- 
ally every  fourth  or  fifth  line — that  is,  for  a  10-foot  interval  every 
50-foot  line,  for  a  20-foot  interval  every  100-foot  line,  for  a  25-foot 


50  PREPAEATION    OF  ILLUSTRATIONS. 

interval  every  100-foot  line,  for  a  50-foot  interval  every  250-foot  line, 
and  for  a  100-foot  interval  every  500-foot  line. 

Uachuring. — The  effect  of  relief  can  be  produced  satisfactorily  by 
hachuring  but  onl}^  by  a  draftsman  who  has  had  considerable  well- 
directed  practice  in  that  kind  of  drawing.  In  a  hachured  map  the 
light  should  seem  to  come  from  the  west  or  northwest — that  is,  the 
darker  parts  should  be  on  the  east  or  southeast  side  of  an  elevation 
and  the  lighter  parts  on  the  west  or  northwest.  The  highest  eleva- 
tion should  be  represented  by  the  darkest  shade  on  the  right  and  by 
a  corresponding  high  light  on  the  left.  The  hachuring  should  begin 
at  the  crest  of  a  peak,  range,  or  butte  and  be  worked  downward 
toward  the  gentler  slopes,  the  lines  being  drawn  farther  apart  and 
made  thinner  until  the  floor  of  the  valley  is  reached  and  the  effect  of 
shadow  is  lost  by  fewer  and  lighter  lines.  On  a  hachured  map  that 
is  made  from  a  contoured  map  somewhat  definite  differences  of 
elevation  may  be  indicated  by  the  intervals  between  the  strokes,  and 
abrupt  changes  in  slope  may  be  indicated  by  shorter  and  heavier 
lines.  The  strokes  should  be  disjointed,  and  they  should  trend  at 
right  angles  to  the  upper  margin  of  a  cliff  and  should  radiate  from 
a  peak.     Figure  6,  B,  represents  satisfactory  hachuring. 

Hill  shading. — Relief  is  more  easily  expressed  by  shading  than  by 
hachuring.  (See  fig.  6,  C,  D.)  The  draftsman  can  best  express  it 
by  this  means  after  he  has  studied  contoured  maps  or  photographs 
of  the  region  mapped,  if  they  are  available,  in  order  that  he  may 
obtain  an  idea  of  the  details  of  its  topography. 

The  special  means  used  to  produce  hill  shading  will  depend  on 
the  character  of  surface  of  the  paper  on  which  the  drawing  is  to  be 
made,  the  size  of  the  map,  the  amount  of  detail  and  refinement  of 
execution  desired,  and  the  amount  of  reduction  to  be  made  in  re- 
producing the  drawing.  For  maps  on  which  it  is  desired  to  show 
some  refinement  of  drawing  and  detail,  a  lithographic  or  wax  crayon 
can  be  used  on  paper  which  has  a  grained  surface.  The  draftsman 
must  express  relief  according  to  the  information  he  has  at  hand, 
whether  detailed  or  general,  and  must  employ  methods  that  accord 
with  the  purpose  of  the  map  and  the  mode  of  reproduction  selected. 
If  a  shaded  relief  map  is  to  be  prepared  for  direct  reproduction  by 
photolithography  and  the  shading  is  to  be  printed  in  a  separate 
color  the  base  map  should  be  completed  first  and  a  light  photo- 
graphic or  blue  print  obtained  on  which  to  add  the  relief  in  black 
lithographic  crayon,  to  insure  perfect  fitting  of  the  relief  and  the 
base;  or  the  relief  can  be  prepared  on  an  oversheet — a  semitrans- 
parent  white  paper  with  sufficient  "  tooth  "  or  grain  to  cut  the  shad- 
ing up  into  minute  dots.  The  shadowless  drafting  table  (see  p.  47) 
is  especially  useful  for  this  purpose.     On  this  oversheet  register 


PREPARATION  OF  ILLUSTRATIONS.  51 

marks  should  be  placed  at  the  four  corners  and  at  severa]  other  points, 
particularly  at  the  intersection  of  parallels  and  meridians. 

For  relief  shading  on  small  black  and  white  maps  Eoss's  hand- 
stipple  drawing  paper  may  be  used.  (See  p.  24.)  By  rubbing  a 
black  wax  crayon  or  pencil  over  the  surface  of  the  paper  the  de- 
sired effect  is  produced  in  fine  dots  or  in  stipple,  which  may  be  varied 
in  density  of  shade  at  the  will  of  the  draftsman.  (See  fig.  6,  C.) 
High  lights  can  be  produced  by  scraping  away  the  chalky  surface  of 
the  paper.  A  lithographic  or  wax  crayon  is  the  best  medium  to  use 
on  this  stipple  paper,  as  on  the  paper  referred  to  in  the  preceding 
paragraph,  for  the  shading  produced  by  it  is  not  so  easily  smeared 
as  that  produced  in  pastel  or  by  a  graphite  pencil.  The  object  of 
using  either  the  rough  paper  or  Ross's  stipple  paper  for  drawings 
that  are  to  be  reproduced  by  photo-engraving  is  to  produce  a  shading 
that  is  broken  up  into  dots  of  varying  sizes,  which  is  essential  in  such 
reproduction. 

Relief  shading  for  maps  can  also  be  made  with  a  brush  in  flat 
washes  of  either  India  ink  or  lampblack.  Such  shading  should  be 
made  only  over  a  blue  print  or  an  impression  of  some  kind  from  the 
map  upon  which  the  shading  or  relief  is  to  be  overprinted.  If  the 
relief  is  expressed  on  the  author's  original  by  contours  the  general 
shapes  of  the  relief  and  the  drainage  lines  can  be  traced  and  trans- 
ferred lightly  in  blue  lines  to  form  a  base  on  which  to  model  the 
shading  and  at  the  same  time  to  make  the  shading  fit  the  streams. 
Such  a  drawing  can  be  photographed  through  a  screen  and  repro- 
duced by  half  tone  (see  fig.  6,  D)  or  mezzotint  as  a  separate  plate 
made  to  overprint  the  map  in  another  color. 

HYDROGEAPHT. 

General  directions. — ^The  drainage  features  of  a  map  should  be  so 
■drawn  as  to  suggest  the  natural  courses  of  the  streams.  Streams 
should  not  be  drawn  in  straight,  hard  lines,  as  such  lines  are  de- 
cidedly unnatural  and  produce  a  crude  effect.  The  course  of  a  river 
may  be  straight  in  general,  but  it  is  likely  to  be  somewhat  sinuous  in 
detail.  If  the  streams  shown  on  a  preliminary  map  are  drawn  in  a 
clumsy  or  characterless  fashion  they  should  be  redrawn  with  a 
freehand  effect  or  made  slightly  wavy,  in  order  that  they  may 
appear  more  natural.  The  gradual  widening  of  streams  from  source 
to  mouth  should  also  be  shown  in  the  drawing.  On  small-scale  maps, 
where  the  eye  can  at  once  see  a  stream  through  its  full  length,  this 
almost  imperceptible  widening  can  be  expressed  by  a  line  of  almost 
uniform  weight  except  for  the  stretch  near  the  source,  where  it  should 
grow  thinner  and  taper  off.  On  maps  which  are  to  be  reproduced 
directly  from  drawings  in  black  and  white  and  which  are  to  show 


52  PREPAEATION   OF  ILLUSTRATIONS. 

both  contour  lines  and  drainage  the  lines  representing  the  streams 
and  other  water  bodies  should  generally  be  drawn  freehand  and 
slightly  heavier  than  the  contour  lines,  which  should  be  sharper  and 
more  precise. 

The  names  of  all  streams  or  other  bodies  of  water  should  be  in 
italic  letters,  those  of  the  larger  streams  being  lettered  in  capitals 
and  those  of  the  smaller  streams  in  capitals  and  lower-case  letters. 
(See  "Lettering,"  p.  53.) 

Water  lining. — The  use  of  water  lining  on  black  and  white  maps 
should  be  limited  to  maps  on  which  the  water  areas  are  not  readily 
distinguishable  from  the  land  areas.  In  rough  drawings  that  are  to 
serve  only  as  copy  for  engravers  a  flat  color  may  be  used  for  water 
areas  and  its  conversion  into  water  lines  specified.  In  base  maps  to 
be  reproduced  in  three  colors  a  light-blue  tint  may  be  used  in  lieu 
of  water  lining,  and  it  can  be  printed  either  flat  or  in  a  fine  ruling 
transferred  to  the  stone  that  is  to  print  the  drainage.  The  engraving 
of  water  lines  is  expensive,  and  the  flat  blue  color  should  generally  be 
preferred. 

Water  lining  usually  consists  of  30  to  45  lines  on  engraved  or 
large  maps,  but  on  small  maps  and  sketch  maps  the  number  may 
be  reduced  as  desired.  Care  should  be  taken  that  the  lines  are  as 
nearly  parallel  as  they  can  be  made  freehand  and  of  even  weight 
or  thickness.  The  first  three  to  six  lines  outside  the  coast  line  should 
be  somewhat  closer  together  than  those  farther  out  and  should  con- 
form closely  to  the  coast  line,  but  the  spacing  between  the  lines  should 
increase  and  the  lines  should  become  almost  imperceptibly  less  con- 
formable to  the  coast  line  as  they  reach  their  outer  limit,  the  last 
three  to  six  being  made  with  the  greatest  care  and  refinement. 
Water-lined  maps  that  are  to  be  reproduced  by  photographic  processes 
should  be  drawn  at  least  twice  publication  size.  The  reduction  will 
bring  the  lines  closer  together,  and  the  reproduction  will  show  a  more 
refined  effect  than  could  possibly  be  produced  by  the  most  skillful 
drawing. 

Good  examples  of  water  lining,  such  as  are  shown  on  the  topo- 
graphic atlas  sheets  of  the  Survey,  should  be  studied  by  draftsmen 
before  they  undertake  such  work. 

CULTTJHAL  FEATURES. 

The  cultural  features  represented  on  a  map  include  "  the  works  of 
man  " —  not  only  cities,  towns,  buildings,  bridges,  railroads,  and  other 
roads,  but  State,  county,  and  other  boundary  lines — in  short,  all  that 
part  of  a  three-color  base  map  which  is  shown  in  black,  the  engraved 
plate  for  the  black  being  called  the  culture  plate.    The  features  named 


U.  S.  GEOLOGICAL  SURVEY 


PREPARATION  OF  ILLUSTRATIONS    PLATE   IV 


Boundary  lines  and  surveyors'marks 

State  or  international  boundary  line. _ 

County  boundary  line 

Township,  section,  and  quarter-section  lines / 

Reservation  boundary  line .  . .  . .  - 

Land  grant  boundary  line ■  ■ ■  • . .  . 

Civil  township  boundary  line —  —  —  ■ — — 

City  and  small  park  boundary  line - 

Boundary  monument _^__. 

Township  and  section  corners  recovered ^ 

Triangulalion  station A 

Bench  mark _ X 

U.  S.  mineral  orlocating  monuments ^  /^60 


Public  works 


Railroad,  single  track 

Railroad,  double  track 

Juxtaposition  of  railroads 

Electric  railroad  and  tramway 

Railroad  in  wagon  road 

Railroad  tunnel. 

Railroad  station 

Electric  power  line 

Wagon  roads,  good 

Wagon  roads,  poor  or  private... 

Trail  orroule  of  travel , 

Telegraph  line 

Telegraph  line  in  roads 

Telegraph  line  on  trail 

Fences,  of  any  kind 

Fence,  stone 

Fence,  worm _ 

Fence,  wire 

Hedge 

City  or  town 

City  or  town  (large  scale! 

Capital 


I    t   I   I    I    I    I    I 


'Large'xaiemapi ^; Small scile  nap i 


?>S^/ 


i^§g^ 

^  -c^aac 

County  seat - (S) 

Towns _-o •■ # 

Buildings 

Ruins * [""■"" 

Post  office ■  /v  ' — '' 

Cemeteries \C£m]     [+]      + 

Church .\-Tr.-.^._..\-.— ^ 

Schoolhouse _ 


Water  features 


Streams 

Intermittent  stream 

Unsurveyed  streams... 

Falls  and  rapids 

Springs  _ 


Glaciers. _  >»s'WW,W>vi*      '"T T~>^^7rV'>'; 

Lakes  or  ponds ^^^^^^  ^ — r^  ~cc«**.«x,3  -^.^    <..^«. 

Intermittent  lake  or  pond ^^?^^^^..\fC -«^^^^^^ 

Marsh,  fresh S^f^^^^  ^m-^ 

Marsh,  salt.... 

Tidal  flat _ _ __^ 

Canal  or  ditch --{  =  -  = 

^-■<^^"-- - - s—        & 

Draw  bridges Bj! 

Ferry  fpoint  upstream).. .._ W^~ 

Dams _ _ _ _ _ 

Locks  (pomt  upstream) 

Wateriirung  and  breakwater 

Relief  features 

Contour  lines ._ 

Hachures  - _ 

Depression  contour ,. 

Woods- _.S 

Amm  above  amber  line 


SYMBOLS  USED  ON  BASE  MAPS 


PREPARATION-  OF  ILLUSTRATIONS. 


63 


in  the  list  below  are  the   cultural  features  referred  to.     (See  PI.  IV 
for  corresponding  symbols.) 


Aqueduct  mains. 

Aqueduct  tunnels. 

Bench  marks. 

Boundary  lines. 

Boundary  monuments. 

Breakwaters. 

Bridges. 

Buildings. 

Cable  lines. 

Camps. 

Canal  locks. 

Canals. 

Cemeteries. 

Churches. 

Cities. 

County  lines. 

Dams. 

District  lin&s. 

Ditches. 

Electric  power  lines 

Fences. 

Ferries. 

Fords. 

Gas  wells. 

Hedges. 


Hospitals. 

Jetties. 

Land-grant  lines. 

Land-section  lines. 

Levees. 

Mains. 

Mineral  monuments. 

Mine  tunnels. 

Mines. 

National  forests. 

National  parks. 

Oil  tanks. 

Oil  wells. 

Open  cuts. 

Park  boundaries. 

Paths. 

Pits. 

Post  offices. 

Precinct  lines. 

Prospects. 

Province  lines. 

Quarries. 


Quarter-section  lines. 
Railroads,  steam  or  elec-  Windmills, 
trie. 


Ranches. 

Reservation  boundaries. 

Reservoirs. 

Roads. 

Ruins. 

Schoolhouses. 

Section  corners. 

Section  linea 

Settlements. 

Shafts. 

Streets, 

Telegraph  lines. 

Towns. 

Township  comers. 

Townships. 

Trails. 

Tramways. 

Triangulation  stations. 

Txmnels. 

Villages. 

Water  mains. 

Water  wells. 

Waterworks. 


LETTERING. 


GENERAL  BIRECTIONS. 


The  cultural  features  are  named  on  maps  by  letters  of  two  distinct 
styles — slanting  gothic  for  public  works  and  roman  for  habitations 
and  civil  divisions.  The  size  of  the  letters  used  should  indicate  in  a 
general  way  the  relative  importance  of  the  feature  or  group  to  which 
they  are  applied,  but  on  some  maps  the  county  seats,  State  capitals, 
and  large  cities  may  be  distinguished  by  different  symbols.  The 
names  of  civil  divisions  are  lettered  in  sizes  depending  on  their 
relative  grade  and  the  size  of  the  area  or  space  in  which  the  names 
are  to  appear. 

The  features  shown  on  a  topographic  map  may  be  broadly  sepa- 
rated into  four  groups  and  are  lettered  as  follows : 

Civil  divisions  (countries,  States,  counties,  townships,  land  grants, 
reservations,  cities,  towns,  villages,  settlements,  schools,  lodges, 
ranches,  etc.),  roman  capitals  or  capitals  and  lower  case. 

Public  works  (railroads,  tunnels,  roads,  canals,  ferries,  bridges, 
fords,  dams,  mains,  mines,  forts,  trails,  etc.),  slanting  gothic  capitals 
(light)  or  capitals  and  lower  case. 


54  PREPARATION"  OF  ILLUSTRATIONS. 

Hydrographic  features  (oceans,  seas,  gulfs,  bays,  lakes,  ponds, 
rivers,  creeks,  brooks,  springs,  wells,  falls,  rapids,  marshes,  glaciers, 
etc.),  italic  capitals  or  capitals  and  lower  case. 

Hypsographic  features  (mountains,  ranges,  peaks,  plateaus,  cliffs, 
buttes,  canyons,  valleys,  peninsulas,  islands,  capes,  etc.),  upright 
gothic  capitals  (light)  or  capitals  and  lower  case. 

The  essential  principles  of  lettering  have  been  described  in  numer- 
ous treatises  and  are  well  understood  by  most  draftsmen.  The  cor- 
rect form  of  each  letter  may  be  learned  from  such  treatises,  but  spac- 
ing and  arrangement  are  best  learned  by  observation  and  experience. 
Good  lettering  will  not  strongly  attract  attention,  but  even  slight 
imperfections  of  form,  spacing,  slant,  and  shading  will  be  quickly 
detected  and  criticized.  Map  letterers  should  note  that  the  name  of 
a  place  or  the  number  of  a  symbol  should  be  put  to  the  right  of  the 
symbol  if  possible  and  a  little  above  or  below  it — not  to  the  left  and 
directly  on  a  line  with  it,  as  Tucsono,  iTo,  Dallaso,  Carsono.  Names 
indicating  large  areas,  if  written  from  west  to  east,  should  curve  with 
the  parallels,  and  all  names  should  be  so  lettered  that "  if  they  should 
fall  they  would  fall  on  their  feet."  Every  name  should  be  distinctly 
legible  but  not  so  conspicuous  as  to  subordinate  the  feature  it  desig- 
nates. Lines  should  therefore  not  be  broken  in  order  to  make  the 
lettering  clear  except  where  there  is  possible  danger  that  the  smaller 
spaces  may  be  filled  up  in  printing.  The  lettering  on  a  map  should 
always  be  so  spaced  that  it  will  properly  fit  the  area  it  is  intended 
to  designate.  In  names  consisting  of  two  or  more  words  the  letters 
should  not  be  closely  spaced  if  wide  spaces  are  left  between  the  words. 
In  numbers,  except  those  used  to  indicate  elevations  on  contour  lines 
or  elsewhere,  thousands  should  always  be  set  off  by  commas. 

Draftsmen  often  draw  bad  forms  for  commas,  quotation  marks, 
apostrophes,  and  question  marks.  The  following  forms  are  correct: 
Comma  ,  ;  quotation  marks  "  "  ;  apostrophe  '  ;  question  mark  ? . 

LETTERING  BY  TYPE. 

Names  and  short  notes  printed  from  type  on  paper,  to  be  cut  out 
and  pasted  in  proper  positions  on  maps  or  other  drawings,  now  fur- 
nish a  large  proportion  of  the  lettering  on  the  Survey's  illustrations. 
The  strips  are  likely  to  become  detached  by  the  repeated  handling 
of  a  drawing,  however,  unless  they  are  securely  pasted  on.  The  best 
results  can  be  obtained  by  having  the  type  printed  on  a  special  brand 
of  "  noncurling "  gummed  paper,  from  which  the  lettering  is  cut 
in  squares  or  strips,  which  are  dampened  and  applied  to  the  proper 
places  on  the  drawing.  In  handling  such  strips  a  pair  of  dentist's 
tweezers  is  useful.  When  mucilage  is  applied  to  printed  strips  of 
ordinary  paper  the  moisture  causes  the  paper  to  warp  or  curl,  often 
so  much  as  to  affect  the  reproduction  of  the  drawing.     This  printed 


U.  8.  GEOLOGICAL  SURVEY 

l2-point    M} 
12'point    -.V.  ,,       x^j. 

U-pomt    i  is-p  Z.\  --;  ]l 

18'point  ""'''  "-^  '^-F'o 


PREPARATION  OF  ILLUSTRATIONS    PLATE  V 


\Z  ^'T!  12-jmnt    NORTH  CAROLINA 
12-point' 


:1 


12-po1nt   WE 
14-poJnt  No»; 


12Si56789 
:   12-poV  ^"'^       '      ■     U-mnt    CONNECTICUT    1  2S  1^567  8  9  0& 

NC  ..        U-p,[^-J^^J8-pomt  ILLINOIS  123^5678900^ 

12-POINT    No.  29       KENTUCKY        1234567890 

12-POINT  NO.  30     MISSOURI     12  3  4  5  6  7  8  9  0, 
12-POINT  No.  31    UTAH    1234567  89 

12-POINT  No.  6       WISCONSIN       12  3  456789  0 
'O-fDr   lO   f-  12-POINT  NO  7     IDAHO     123456789  0 

,^  „^,.,-r  ^.  ''^'^*-  '"^"'^  12-POlN  12-POINT  No.  8  OHIO  12  34  5678 
l-^-r^f^ll^  I  /^C  /2-P  12-P  12-POI  14P01NT  ALABAMA  1234567890 
lO-fDQIhJ-r  l\  12-PC  12-F  12-PC  12  point  WEST  VIRGINIA  WYOMING  123456789  0. 
12_  14.POI''*-PO'"'  '^''' "'  PENNSYLVANIA  1234567890 
12-POIN  7\  ^  ^'^'  1  a'i  12-point   '8-point    NORTH  DAKOTA    1  2  3  4  5  6  7  8  9  Q 

19  POINT  n!^^"^  12 P(i4-point24-point  UTAH  123456789 

'^"'    ^^"^'     '^    14-P  18-DOin' ^""'^™'     WSTRICT  OF  COLUMBIA     1234567890 

12    POINT'   \2qq\^^'^^  HA         l^-Point    MASSACHUSETTS   1234567890 

hT>  r-w^iivJ  i/  -^S-P^'P'^^-P^^"^  OREGON  1234567890 
12-POIN!  '"^"P^'  oi  12-point  14- POINT  (ii:()K(ilA  I  2  .'U  o  (5  7  S  9  0 
1  A    OrMMT^  18-pC  14-poin11(5-P()INT  KANSAS  1  2;ur)(i  7n9(> 

i^-rUIINl  ^  ^^■P'^18-poi>^-I'<>I>'I^  INDIANA  1  2  ;U  ;>  (} 
Z4-l4-Pj^P(^i)(i.l>()IXT  MAINK  1L>845 
i2-poii8-]i6.p(i24-P()INT  OHIO   12:U 

18-point    ^18-p IB- 20-1^0/^  pru VT  1  oo  1 

24-poi|  i^i  ^^  24-1^1:1 ;  ^^A/r^ 

12-poto  d|  lt|;;^30-POTNT  12  345  6 

14-point  1 2o|  ^  36-POTNT  1284 
M:l736-P01NT1284 

18-POI136-P01NT  1284 

20-POINT  MAINE   12345 

24-P()INT  OHIO  12  3  4 

30-POINT  12  3456 

36-POINT1234 


REDUCTION  SHEET  USED  IN  LETTERING  ILLUSTRATIONS. 

The  largest  size  shows  the  letters  unreduced;  the  other  sizes  show  the  letters 
reduced  as  indicated  in  the  margin. 


PREPARATION  OF  ILLUSTRATIONS. 


55 


lettering  is  generally  used,  however,  only  for  headings,  titles,  notes, 
and  other  matter  that  stands  alone;  it  should  not  be  used  for  the 
geographic  names  in  the  body  of  a  map  unless  only  a  few  names  are 
to  appear,  for  the  strips  of  paper  bearing  the  names  may  obscure 
parts  of  the  map.  The  reproduction  of  tliis  lettering  by  photo- 
engraving or  photolithography  gives  results  superior  to  those  ob- 
tained from  hand  lettering  unless  each  letter  is  made  with  the  utmost 
care,  work  which  is  considered  a  waste  of  time. 

Type  is  used  also  for  prmting  lettering  directly  on  a  drawing 
exactly  in  proper  position,  by  a  special  type  holder,  somewhat  like 
a  self-inking  stamp. 

Most  of  the  styles  and  sizes  of  type  now  used  on  maps  in  the  Sur- 
vey's reports  are  shown  in  Plate  V. 

If  a  drawing  is  to  be  reduced  one-half  the  smallest  type  used 
should  be  about  2  millimeters  in  height;  if  it  is  to  be  reduced  one- 
third  the  smallest  type  used  should  be  about  1.5  millimeters  in 
height;  and  so  on.  No  letter  whose  vertical  height  after  reproduc- 
tion would  be  less  than  about  1  millimeter  should  be  used,  and  the 
larger  lettering  should  bear  a  proper  relation  to  the  smaller.  Sheets 
showing  the  styles  of  type  in  use  by  the  Survey,  in  full  size  and  re- 
duced one-fourth,  one-third,  two-fifths,  one-half,  three-fifths,  two- 
thirds,  and  three-fourths,  will  be  furnished  on  request'.  If  a  draw- 
ing is  to  be  reduced  one-half,  for  example,  the  sheet  that  has  been 
reduced  one-half  will  show  the  size  of  the  lettering  on  the  printed 
plate,  so  that  the  draftsman,  by  referring  to  the  sheet  showing  the 
reduction  he  desires,  can  select  type  of  a  size  that  will  be  legible. 
Plate  V  shows  a  part  of  this  reduction  sheet. 


ABBEEVIATIONS. 


The  following  are  the  correct  forms  for 
maps  and  other  illustrations : 


abbreviations  used  on 


A. 

Arroyo. 

Is. 

Islands. 

Pk. 

Peak. 

B.  M. 

Bench  mark. 

Jc. 

Junction. 

P.  O. 

Post  office. 

Bdy. 

Boundary. 

L. 

Lake. 

Pt. 

Point, 

Br. 

Branch,  bridge. 

Lat. 

Latitude. 

R. 

Range,  river. 

C. 

Cape. 

Ldg. 

Landing. 

Res. 

Reservation, 

Can. 

Canal,  canyon. 

L.  S.  S. 

Life-saving  sta- 

ervoir. 

Cem. 

Cemetery. 

tion. 

R.  H. 

Road  house. 

<^o. 

County. 

L.  H. 

Lighthouse. 

S. 

South. 

Cr. 

Creek. 

Long. 

Longitude. 

Sd. 

Sound. 

E. 

East. 

M.  P. 

Milepost. 

S.  H. 

Schoolhouse. 

EL 

Elevation. 

M.  M. 

Mineral  monu- 

Sta. 

Station. 

Est. 

Estuary. 

ment. 

Str. 

Stream. 

Fk. 

Fork. 

Mt. 

Mount. 

T. 

Township. 

Ft. 

Fort,  foot. 

Mtn. 

Moimtain. 

Tel. 

Telegraph. 

Gl. 

Gulch,  glacier. 

Mts. 

Mountains. 

W. 

West. 

Hbr. 

Harbor. 

N. 

North. 

1. 

Island. 

Pen. 

Peninsula. 

res- 


56  PREPAKATION  OF  ILLUSTRATIONS. 

Words  like  mount,  river,  point  should  not  be  abbreviated  where  they 
form  a  part  of  the  name  of  a  city  or  town,  as  Rocky  Mount,  Fall 
River,  West  Point.  Neither  the  word  nor  the  abbreviation  for  rail- 
road or  railway  should  be  placed  on  a  map ;  the  chartered  name  (or 
initials  of  the  name)  and  the  road  symbol  are  sufficient. 

Names  of  States  and  Territories  should  be  abbreviated,  where 
abbreviation  is  necessary,  as  follows: 


Ala. 

Ga. 

Minn. 

N.  J. 

Tenn. 

Ariz. 

lU. 

Miss. 

N.  Mex. 

Tex. 

Ark. 

Ind. 

Mo. 

N.  Y. 

Va. 

Calif. 

Kans, 

Mont. 

Okla. 

Vt. 

Ck)lo. 

Ky. 

Nebr. 

Oreg. 

Wash. 

Conn. 

La. 

Nev. 

Pa. 

W.  Va. 

D.  G. 

Mass. 

N.  C. 

R.  I. 

Wis. 

Del. 

Md. 

N.  Dak. 

S.  C. 

Wye. 

Fla. 

Mich. 

N.  H. 

S.  Dak. 

Alaska,  Guam,  Hawaii,  Idaho,  Iowa,  Maine,  Ohio,  Samoa,  and 
Utah  should  be  written  in  full. 

The  abbreviations  used  on  the  margins  of  maps  for  subdivisions 
of  land  should  be  as  follows  (note  punctuation)  :  T.  2  N.,  R.  3  W. 
On  large-scale  plats  the  marginal  lettering  should  be  as  follows: 
N.  i  NE.  i  sec.  1,  T.  7  N.,  R.  2  W. ;  fractional  sees.  2  and  35,  Tps. 
7  and  8  N.,  R.  2  W.;  NW.  i  sec.  20,  T.  7  N.,  R.  2  W.  In  spelling 
fractions  use  half  and  quarter,  not  one-half  and  one-quarter. 

The  abbreviated  forms  of  such  names  as  North  Fork  and  South 
Fork  should  be  N.  Fork  and  S.  Fork,  not  North  Fk.  and  South  Fk. 

Additional  abbreviations  used  on  illustrations  are  as  follows : 

N.  for  north,  NE.  for  northeast,  NNE.  for  north-northeast,  etc.  Capitalize 
directions  affixed  to  street  names,  as  NW.,  SE.  (1800  F  St.  NW.). 

Sec.  and  sees,  for  section  and  sections  before  a  number.  Capitalize  only  at  the 
beginning  of  a  line  or  sentence. 

a.  m.  and  p.  m.  for  antemeridian  and  postmeridian,  as  4.30  p.  m.  Lower- 
case unless  in  line  of  caps. 

&  in  names  of  corporations  or  companies.  On  Survey  miscellaneous  maps 
*■  and  "  is  spelled  out  in  railroad  names. 

B.  t.  u.  for  British  thermal  units. 

bbl.,  bbls.  for  barrel,  barrels. 

bu.  for  bushel  or  bushels. 

c.  c.  for  cubic  centimeter. 

cm.  for  centimeter. 

cwt.  for  hundredweight. 

dwt.  or  pwt.  for  pennyweight. 

oz.  for  ounce  or  ounces. 

etc.  (not  &c.)  for  et  cetera. 

ft.  for  foot  or  feet. 

H.  m.  s.  for  hours,  minutes,  and  seconds.     (Use  capital  H.) 

in.  for  inch  or  inches. 

kw.  for  kilowatt  or  kilowatts 

£  s.  d.  for  pounds,  shillings,  and  pence. 

per  cent  (omitting  period)  for  per  centum.     Spell  out  percentage. 


V.  S.  GEOLOGICAL  SURVEY 


PREPARATION  OF  ILLUSTRATIONS    PLATE  VI 


175-LINE   SCREEN. 


150-LINE   SCREEN. 


133-LINE  SCREEN. 


120-LINE  SCREEN. 


100-LINE   SCREEN. 


65-LINE   SCREEN. 


HALF-TONE    CUTS   SHOWING   EFFECT    OF    SEVERAL    STANDARD 
SCREENS  IN  THE  REPRODUCTION  OF  THE  SAME  DETAIL. 


PREPARATION  OF  ILLUSTRATIONS.  57 

ser.  for  series. 
St.  for  Saint  or  street. 

U.  S.  Army  for  United  States  Army,  as  distinguished  from  United  States  of 
America  (U.  S.  A.), 
yd.,  yds.  for  yard,  yards. 

The  names  of  certain  months  may  in  some  places  be  abbreviated ; 
those  of  others  should  invariably  be  spelled  out.  The  following  are 
the  correct  forms : 

Jan.  Apr.  July  Oct. 

Feb.  May  Aug.  Nov. 

Mar.  June  Sept.  Dec. 

The  abbreviations  for  number  and  numbers  before  figures  are  No. 
and  Nos.  The  o  should  never  be  raised,  as  in  N°.  The  abbreviation 
for  Mac  is  Mc,  not  M^ 

All  periods  should  be  omitted  from  abbreviations  used  in  the  body 
of  a  map  unless  their  omission  would  cause  misunderstanding.  They 
are  generally  unnecessary,  and  if  used  on  some  maps  they  are  likely 
to  be  mistaken  for  symbols  representing  certain  features,  such  as 
houses  or  flowing  wells,  if  either  are  shown.  Periods  used  on  draw- 
ings that  are  to  be  reproduced  "  direct' "  or  photomechanically  should 
always  be  slightly  exaggerated. 

NAMES  OF  KAILEOADS. 

The  names  of  railroads  may  be  written  in  full  or  abbreviated,  in 
accordance  with  the  kind  of  map  and  the  space  available.  On  a 
sketch  map  in  black  and  white  the  initial  lettei-s  are  generally  suf- 
ficient. On  a  more  detailed  map,  if  there  is  room  enough,  the  names 
may  be  spelled  out.  As  already  stated,  neither  the  words  "  railroad  " 
and  "  railway  "  nor  the  abbreviations  R.  R.  and  Ry.  should  be  used 
on  a  map. 

MAKE-UP   OF  MAPS. 
FOEMS  FOE  CEETAIN  FEATTJEES. 

The  proper  forms  for  certain  features  of  maps,  such  as  the  borders, 
titles,  explanations,  bar  scales,  captions,  arrows  indicating  true  north 
and  magnetic  declination,  source,  and  authorship,  are  show^n  in  Plate 
VII.  Note  particularly  the  style  and  position  of  the  marginal 
matter. 

50EDEE. 

A  finished  map  border  is  used  or  omitted  according  to  the  kind 
of  map  prepared.  Diagrammatic  maps  and  maps  on  which  no  par- 
allels and  meridians  appear  do  not  need  finished  borders.  On  a  map 
that  shows  complete  areal  geologic  or  other  coloring,  such  as  a  map 
in  a  Survey  geologic  folio,  the  border  lines  tend  to  destroy  the  sim- 
ple effect  of  the  whole  map.  On  a  map  that  is  not  completely  colored 
and  on  all  very  large  maps  borders  are  really  necessary.     If  borders 


68  PREPAKATION  OF  ILLUSTRATIONS. 

are  used,  however,  the  space  between  the  neat  line  and  the  outer  line 

of  the  border  should  be  only  sufficient  to  provide  proper  space  for 

the  numbers  showing  latitude  and  longitude  or  township  and  range. 

A  simple  rule  ^  for  determining  the  width  of  this  space  is  as  follows : 

Divide  the  sum  of  the  dimensions  of  the  map  by  2  and  find  the 

square  root  of  the  quotient,  which  will  represent  the  width  of  the 

border  in  sixteenths  of  an  inch.    Example :  Map  is  20  by  30  inches ; 

20  +  30 

— 2 —  ^  25 ;  square  root  of  25  =  5 ;  width  of  border  =  -f-^  inch. 

The  numbers  showing  latitude  and  longitude  should  be  in  shaded 
arable  numerals  and  those  showing  township  and  range  in  gothic. 
The  symbols  for  degree,  minute,  and  second  should  not  be  crowded. 
On  a  map  that  has  no  added  border  lines  the  numbers  should  be  in 
hair-line  gothic. 

TITLE. 

The  title  of  a  map  should  be  in  roman  letters  and  if  placed  at  the 
lower  margin  should  generally  be  arranged  in  two  lines,  unless  it 
is  short.  If  it  forms  two  or  more  lines  the  lines  should  be  well  bal- 
anced. The  first  line  should  describe  the  position  of  the  area;  the 
second  line  should  state  the  purpose  of  the  map,  as 

MAP  OF  BUTTE  AND  VICINITY,  MONTANA 

SHOWING   LOCATION    OF    MINES    AND    PBOSPECTS. 

A  title  placed  inside  the  border  of  a  map  should  be  arranged  in 
a  series  of  lines,  generally  beginning  with  "  Map  of  "  or  "  Geologic 
map  of."  and  the  line  showing  the  dominant  part  of  the  title  should 
be  emphasized  by  larger  lettering,  thus : 

MAP  OF 

THE  VICINITY   OF  BUTTE 
MONTANA 

SHOWING   LOCATION    OF   MINES    AND   PROSPECTS. 

The  name  of  the  author  or  compiler  of  a  map  or  of  the  person 
supplying  the  geologic  or  other  data  shown  on  it  may  be  placed  either 
beneath  the  title  or  in  the  lower  right  corner,  just  below  the  border 
line,  and  the  names  of  the  topographers  or  the  source  of  the  base 
should  be  stated  in  the  lower  left  comer,  just  below  the  border  line. 
If  the  title  is  placed  inside  the  border  all  notes  giving  credit  for 
any  part  or  features  of  the  map  may  be  placed  beneath  the  title  or 
scale.    (See  PL  VII.) 

EXPLANATION. 

The  symbols,  patterns,  or  colors  used  on  a  map  should  be  given  in 
a   series   of   rectangles   or   "boxes,"   accompanied   by   explanatory 

•Worked  out  by  Martin  Solem,  of  the  U.  S.  Geo\ogical  Survey. 


U.  S.  GEOLOGICAL  SURVEY 


V.  S.  GEOLOGICAL  SURVEY 


PREPARATION  OF  ILLUSTRATIONS   PLATE  VII 

PROFESSIONAL  PAPER  Sfl7      PLATE  Vn 

EXPLANATION 

SEGMENTARY  ROCKS 


86  00 


^5,_ 


e 

5 

A 

^ 

2 

1 

7 

8 

9 

10 

11 

12 

J8 

17 

16 

15 

l-» 

13 

19 

20 

21 

22 

23 

2* 

30 

29 

2B 

27 

26 

25 

31 

- 

33 

34 

35 

36 

DIAGRAM     OF    TOWNSHIP 


<> 


1 

Qal 

q; 

Alluvium 

iftream  depoeitt) 

Tt 

Telluride  conglomeratt 
ipebbUA  and  bouideri) 

UNCONFORMITY 

Kc 

c 

Carlile  shale 

{dark  HhaJe  containing 
iron  concreiiont ) 

1 

Kg 

Greenhorn  limestone 

( jointed  dovt-colored 

titnegtone  untk*  •  *  ) 

Jsd 

Sundance  formation 

(alUmating  >andxtone») 

"Sd 

Dolores  formation 

(caJeareowt  shale  and 
conglomerate) 

■2 
1' 

Ch 

1 

Hermosa  formation 

(mndstone.  shale,  and 
limestone,  of  grayiAh**) 

DC 

Surv«y«d  i 


87*00' 


B«s«  from  U.  S.  Geoloj^ic 
tOpOfrAphic  map 


GEOLOGIC   MAP    OF 


25  Mies 


£0      25  KLometers 


Contour  in(er\a]  50 feet 

Dabun  is  metui  sea  levvl 

1920 


Ouray  limestone 
(Whxte  or  Ivght^nU 
aaccharoidai  tirmntone) 


Ignacio  quartzite 

(/hin-bfdded  ffray  or 
pink  vavy  qnartzii^) 


Schist 

(dense  bluish-ffray  Tocks 

with  subordinate  •  •  ) 


IGNEOUS  ROCKS 


Tp 


Picayune  andesite 

(intrusixc  masses  and 

sheets) 


Schist  and  gneiss 

(quartz-mica  schist, 

congUmwraU,  and  *  • 


Fault 

Strike  and  dip 

$ 

Axis  of  anticline 


DETAILS  OF  THE  MAKE-UP  OF  A  GEOLOGIC  MAP 


PREPAKATION   OF  ILLUSTRATIONS.  59 

terms  in  the  form  shown  in  Plate  VII,  headed  "  Explanation."  If 
the  explanation  is  small  a  convenient  place  for  it  on  some  maps 
may  be  found  within  the  neat  lines.  If  no  space  is  available  there, 
or  if  it  is  so  large  that  there  is  not  room  to  place  it  there  with- 
out obscuring  other  details,  it  may  be  placed  either  vertically  along 
the  right  margin,  as  shown  in  Plate  VII,  or  horizontally  under  the 
title.  A  geologic  explanation  should  preferably  be  arranged  ver- 
tically, as  in  Plate  VII,  so  as  to  show  the  relative  age  of  the  forma- 
tions by  the  positions  of  the  boxes.  This  explanation  should  be 
carefully  worked  out  in  pencil  by  the  draftsman  and  approved  by 
the  committee  on  geologic  names  before  it  is  drawn  in  inl?:,  in  order 
to  save  time  in  making  corrections. 

In  lettering  the  explanation  roman  letters  or  type  should  be  used 
for  the  titles  under  the  boxes  and  italic  of  smaller  size  for  the  sub- 
titles or  descriptive  detail,  which  should  be  inclosed  in  parentheses. 
The  names  of  geologic  periods  and  systems  should  be  in  gothic  capi- 
tals, the  names  of  series  or  groups  should  be  in  italic  lower  case,  and 
the  limit  of  each  period,  system,  or  group  should  be  indicated  by 
braces.  The  general  style  and  arrangement  shown  in  the  Survey's 
geologic  folios  should  be  followed,  and  this  and  the  arrangement  of 
other  matter  is  shown  in  Plate  VII.  Care  should  be  taken  not  to  crowd 
the  explanation,  and  if  corrections  are  necessary  they  should  be  so 
made  that  each  line  of  the  matter  in  which  they  appear  will  be  prop- 
erly spaced. 

The  explanation  for  a  map  that  is  to  be  engi-aved  or  to  be  repro- 
duced by  lithogi'aphy  need  only  be  sketched  in  to  show  general  style 
and  arrangement.  The  engraver  or  the  lithographer  will  supply 
such  matter  in  proper  form  according  to  specifications.  For  direct 
reproduction,  however,  as  by  photolithography  or  zinc  etching,  the 
lettering  must  either  be  carefully  drawn  with  pen  or  printed  from 
type  on  slips,  which  are  pasted  on  the  drawing. 

GRAPHIC  SCALES  FOE  MAPS. 

A  bar  scale  for  miles  or  feet  should  be  given  on  every  map,  and  if 
the  map  is  of  international  interest  the  metric  scale  should  be  given 
just  beneath  the  scale  of  miles  or  feet.  The  accepted  designs  for 
these  scales  are  shown  in  figure  7.  The  scale  should  be  accompanied 
by  any  necessary  statement  pertaining  to  the  base  map,  such  as  "  Con- 
tour interval  20  feet,"  "  Datum  is  mean  sea  level."    The  fractional 

scale  (^  ,  for  example)  should  be  given  an  all  except  the  more 

simple  kinds  of  maps,  and  the  date  of  publication  should  also 
appear  just  below  the  scale  or  scales.  The  single- line  bar  scale 
should  be  used  only  on  small  or  simple  maps.  The  length  of 
the  bar  scale  must  depend  on  the  size  of  the  map  and  the  space 
available.  Those  shown  in  figure  7  were  made  over  blue  prints  from 
scales  used  by  the  Survey.  ' 

861754^ — 49 5  '^ 


60 


PREPARATION  OF  ILLUSTRATIONS. 


To  make  a  bar  scale  for  a  map  of  unknown  scale  that  shows  only 
a  single  meridian  and  parallel,  or  for  a  map  on  which  no  meridians 


Scale    500,000 


25  Miles 


L  .1  .l.u  ' 


25  Kilometers 


Contour  interval  200  feet. 

Doutwn.  is  mjaarv  secu  level. 

1920 


5.000 


10,000  Feet    o 


Horizontal  andvertica!  scale  _ 

500  1000  1500  Feet 


Vertical  scale 

200  40O 


eooFeet 


Scale  1,500,000 

10  EG 


-loMiles 


100& 


600 


1918 

1000 


3000  Feet 


10 


15  Miles 


0 


10 


15 


20  Kilometers 


Figure   7. — Designs  for  bar  scales. 

or  parallels  are  shown,  first  ascertain  the   distance   between  two 

points  shown  on  the  map  by 
reference  to  other  authentic 
maps.  If,  for  example,  the 
distance  between  two  such 
points  is  16.315  miles  draw 
a  horizontal  line  («  in  fig. 
8)  representing  this  dis- 
tance on  the  map,  and  at 
its  end,  at  right  angles 
to  it,  draw  another  line  (&) 
actually  measuring  16.315 
units  of  any  convenient  de- 
nomination.  Draw  a 
straight  line  (c)  diagonally 
between  the  ends  of  lines 
aand&.  Then  set  off  on  line 
h  any  convenient  number 
of  the  units  selected,  say  5 
or  10,  and  project  from  the 
points  set  off  lines  exactly 
parallel  with  line  c  to  line 
a.  The  distance  and  the 
nimiber  of  the  units  thus 


15  Miles 


Figure  8.- 


-Method  of  making  a  bar  scale  for  a 
map  of  unknown   scale. 

marked  on  line  a  will  indicate  the  number  of  miles  covered  by  that 
distance  on  the  map,  as  shown  in  figure  8. 


U.  a  GEOLOGICAL  SURVEY 

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PREPARATION  OF  ILLUSTRATIONS  PLATE  VXH 


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38 


PATTERNS  USED  TO  SHOW  DISTINCTIONS  BET^VEEN 

AREAS  ON  BLACK  AND  WHITE  MAPS 

Contraata  may  be  increased  by  varying  the  direction 

and  spacing  of  lines 


PREPAKATION   OF   ILLUSTRATIONS.  61 

SYMBOLS. 

Symbols  should  be  drawn  with  as  much  care  as  letters,  though  to 
a  critic  they  may  not  appear  so  bad  as  poor  lettering  unless  he  finds 
them  glaringly  large  or  so  small  that  he  can  discover  or  identify  them 
only  with  difficulty.  The  size  of  a  symbol  must  depend  on  its  im- 
portance on  the  map  bearing  it.  On  a  map  that  shows  numerous 
mines,  for  instance,  the  crossed  hammers  or  the  symbols  for  shafts 
should  be  not  only  visible  but  conspicuous.  The  draftsman  who  is  to 
make  such  a  map  must  know  beforehand  how  much  his  drawing  will 
be  reduced  in  reproduction  and  must  make  the  symbols  in  proportion 
to  the  reduction.  The  symbols  shown  in  Plate  II  (p.  20)  should  be 
used  in  all  the  Survey's  illustrations  where  they  are  appropriate. 

ABEAL  PATTERNS  FOR  BLACK  AND  WHITE  MAPS. 

The  conventional  patterns  used  on  a  map  to  distinguish  separate 
areas,  chiefly  geologic,  are  shown  in  Plate  VIII.  The  patterns  shown 
represent  the  proper  combinations  of  lines,  dots,  and  other  forms  and 
should  be  spaced  openly  or  closely  according  to  the  size  of  the  area 
covered,  the  contrast  needed  between  areas,  and  the  general  clearness 
and  effect  desired.  If  a  map  is  to  show  both  small  and  large  areas 
dense  or  closely  spaced  patterns  should  generally  be  used  for  the 
smaller  areas,  even  if  they  may  be  required  for  some  fairly  large  areas 
representing  the  same  formation  or  condition.  On  the  other  hand, 
open  patterns  should  be  used  for  large  areas.  Again,  it  may  be  neces- 
sary to  make  certain  areas  more  conspicuous  than  others,  and  this 
effect  can  be  best  produced  by  drawing  the  lines  closer  together  rather 
than  by  making  them  heavier,  unless  the  area  covered  is  small  or  un- 
less a  closely  spaced  similar  pattern  has  been  or  will  be  used  else- 
where on  the  map.  Heavy-line  patterns  or  bars  are  not  desirable. 
The  lines  forming  a  pattern  should  generally  be  drawn  at  an  angle  of 
45  °  to  the  sides  of  the  map ;  they  should  be  drawn  vertically  or  hori- 
zontally only  in  small  areas  or  in  areas  not  crossed  by  meridians  or 
parallels  or  by  other  lines  running  in  the  same  direction.  The  lines 
should  preferably  run  across  the  long  axis  of  an  area,  not  parallel 
to  it,  and  the  predominating  trend  or  general  direction  of  the  areas 
of  one  geologic  formation  on  a  map  should  decide  the  direction  of 
the  lines  for  all  areas  of  that  formation  on  the  same  map,  even  if  the 
rule  must  be  violated  on  some  of  the  minor  areas. 

An  effort  should  always  be  made  to  produce  a  pattern  that  is 
subordinate  in  strength  to  the  main  lines  of  the  base  map  on  which 
it  is  drawn.  In  black  and  white  maps,  as  in  colored  maps,  unlike 
patterns  should  be  placed  next  to  each  other.  If  they  are  so  placed 
it  may  not  be  necessary  to  rule  the  lines  on  two  adjacent  areas  in 
opposite  directions  to  produce  needed  distinctions.  A  section  liner 
or  other  ruling  device  should  be  used  in  drawing  line  patterns  in 


62 


PREPAKATION    OF   ILLUSTRATIONS, 


order  to  produce  uniformly  even  spacing.    The  application  of  six  o! 
these  conventional  patterns  to  a  base  map  is  shown  in  figure  9. 


FiaoRB  9. — Map  bearing  six  areal  line  patterns. 


PEEPAKATION   OF  ILLTJSTKATIONS.  63 

STANDARD  COLOKS  FOH  GEOLOGIC  HAPS. 

The  standard  series  of  colors  for  systems  of  sedimentary  rocks  is 
shown  on  the  maps  in  the  Survey's  geologic  folios  but  is  subject  to 
modifications  for  use  on  maps  in  other  Survey  reports.  Each  system 
is  represented  by  a  different  color,  and  if  there  are  two  or  more  forma- 
tions in  one  system  they  are  generally  distinguished  by  using  different 
patterns  composed  of  straight  parallel  lines  in  the  same  color.  The 
patterns  for  subaerial  deposits  (chiefly  Quaternary)  are  composed  of 
dots  or  circles,  or  combinations  of  both,  and  may  be  printed  in  any 
color,  but  the  color  most  often  used  is  yellow  or  ochraceous  orange. 
No  specific  colors  are  prescribed  for  igneous  rocks,  but  if  onlj  a  few 
areas  are  shown  red  or  pink  is  preferred.  The  colors  used  for  igneous 
rocks  are  generally  more  brilliant  and  purer  than  those  used  for  sedi- 
mentary rocks.  For  small  areas  they  are  used  "  solid  " ;  for  large  areas 
they  are  reduced  in  tone  by  the  use  of  a  suitable  cross-line  pattern  or 
"  reticle."  Metamorphic  rocks  are  represented  by  short  dashes  irregu- 
larly placed.  These  dashes  may  be  in  black  or  in  color  over  a  ground 
tint  or  over  an  imcolored  area,  or  they  may  be  in  white  on  a  ground 
tint  or  pattern.  The  standard  colors  used  for  the  sedimentary  series 
covering  the  12  systems  recognized  by  the  Geological  Survey  are: 
Quaternarj'-  (Q),  ochraceoiis  orange;  Tertiary  (T),  yellow  ocher  and 
isdbeUa  color;  Cretaceous  (K),  olive-green  or  rainette-green;  Jurassic 
(J),  Mue-green  or  niagara-green;  Tr'mssic  C^),  light  peacock-bluo 
or  bluish  gray-green;  Carboniferous  (C),  blue  or  columhia-hlue; 
Devonian  (D),  gra.y-puri)le  or  heliotrope-gray ;  Silnr'mn  (S),  purple 
or  argyle-purple;  Ordovician  (0),  red-purple  or  rocellin-purple ; 
Cambrian  (-G),  brick-red  or  eti^uscan  red;  Algonkian  (A),  terra  cotta 
or  onion-shin  pirOc ;  Archean  (/R),  gray-brown  or  drah}^ 

BEDUCTIOK  OB  ENLABGEMENT  OF  HAFS. 

The  following  is  the  simplest  and  most  accurate  method  of  mark- 
ing the  reduction  or  enlargement  of  a  map  to  a  selected  scale :  Meas- 
ure the  distance  between  the  extreme  meridians  along  one  of  the 
parallels.  (See  fig.  10.)  Convert  this  distance  into  miles  by  multi- 
plying the  number  of  degi-ees  it  covers  (say  3)  by  the  number  of 
miles  in  a  degree.  A  degree  on  the  forty-third  parallel,  for  example, 
is  50.669  miles,^^  which  multiplied  by  3  equals  152.007  miles.  Then 
draw  a  line  on  the  margin  of  the  map,  outside  the  border,  the  exact 
length  of  the  3  degrees,  and  just  below  this  line  draw  another  line 
representing  the  same  number  of  miles  (152.007)  on  the  scale  to 
which  the  map  is  to  be  reduced  or  enlarged.  Then  mark  to  reduce  or 
enlarge  the  upper  line  to  the  lower  line,  as  shown  in  figure  10,    A 

^0  Names  printed  in  italic  are  from  "  Color  standards  and  nomenclature,"  by  Kobert 
Ridgway. 

"  See  U.  S,  Geol.  Survey  Bull.  650,  p.  37,  1916. 


64 


PREPAKATION  OF  ILLUSTRATIONS. 


lono^  line  will  reduce  error  and  give  greater  accuracy  than  a  short 
one,  and  therefore  as  great  a  distance  should  be  set  off  as  possible. 
The  number  of  miles  represented  by  both  lines  and  the  fractional 
scale  to  which  it  is  to  be  reduced  should  be  stated  on  the  drawing, 
for  permanent  record. 

Maps  that  will  bear  reduction  without  affecting  the  clearness  of 
the  details  they  show  may  be  reduced  to  fit  the  book  in  which  they 
are  to  appear,  regardless  of  definite  scale.  The  reduction  for  such 
maps  is  best  marked  in  fractions,  as  "  1/2  off,"  "  1/3  off,"  "  %  off."    If 


4f 


/Btrfctce/^^  Zt^,3°<m.  ^3' fiv/t-^U&JOsZ.ooy  miLi  m  -m^) 


^ i^tu — S.IS4TU  aU*^i''nc€'  m.  acub^  /:Z,S00,O0O 


Figure  10. — Diagram  showing 


method   of  marking  maps   for   reduction   or  enlargement 
(for  record). 


the  size  needed  is  not  exactly  represented  by  these  fractions  it  should 
be  indicated  in  inches,  as  "  Reduce  this  line  to  7 J  inches,"  or  "  Ive- 
duce  to  4f  inches  in  width." 

DIAGRAMS. 

In  preparing  a  diagram  a  draftsman  should  endeavor  to  make  its 
parts  and  relations  perfectly  clear  to  the  reader.  He  should  study 
the  drawing  or  material  furnished  by  the  author  until  he  fully  under- 
stands it  and  should  endeavor  to  reproduce  it  simply  and  legibly. 
Any  lettering  that  may  be  needed  should  generally  be  in  plain 
upright  or  slanting  gothic  type  (see  PI.  IX),  or  it  may  be  in  roman. 

A  diagram  should  generally  be  drawn  on  bristol  board  or  on  blue- 
lined  section  paper  and  should  be  marked  for  reduction  to  the 
minimum  size.  It  should  bear  no  title,  as  the  title  will  be  set  up  in 
type  by  the  printer. 

SECTIONS. 

The  sections  used  in  geologic  reports  are  of  two  widely  different 
kinds.  One  shows  only  the  broader  relations  of  parts;  the  other 
shows  details  of  structure  as  well  as  relations.  One  is  diagranmiatic ; 
the  other  is  more  realistic  and  graphic.  The  draftsman  should  pre- 
pare all  sections  strictly  according  to  the  copy  supplied  by  the  author 
but  should  use  proper  symbols  and  make  a  moi'e  finished  drawing. 
The  various  kinds  of  sections,  most  of  them  geologic,  are  described 


U.  S.  GEOLOGICAL  SURVEY 


PilEPARATION  OF  ILLUSTRATIONS    PLATE  IX 


=!     70 

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5                                                                    E 

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1880     1890     1900     1910     I3» 


DIAGRAMS  AND  CURVES. 


PREPARATION   OF  ILLUSTRATIONS. 


65 


on  pages  29-30,  and  the  conventions  used  to  express  lithologic  char- 
acter are  shown  in  Plate  III. 

Detailed  drawings  of  this  kind,  though  entirely  conventional,  can 
be  so  prepared  as  to  give  a  satisfactory  expression  of  nature.  The 
draftsman  should  study  well-prepared  sections  in  Geological  Sur- 
vey reports  and  should  learn  the  details  of  folding  and  faulting  from 
textbooks.  He  should  first  ascertain  whether  or  not  the  vertical 
scale  in  the  original  section  has  been  unduly  exaggerated,  and  if  so 
he  should  confer  with  the  author  with  a  view  to  reducing  the  exag- 
geration as  much  as  possible.  He  should  submit  to  the  author  all 
questions  as  to  doubtful  points,  as  well  as  all  suggestions  for  im- 
provement in  expression,  before  he  makes  any  changes,  and  he  should 
make  corrections  only  on  the  author's  approval.  A  seeming  inac- 
curacy in  an  author's  drawing  may  be  a  faithful  representation  of 
natural  conditions.  For  example,  a  formation  that  seems  to  be 
omitted  by  inadvertence  in  drawing  may  really  "  pinch  out "  at  a 
point  represented  in  the  section.    (See  a  on  fig.  11.) 


w. 


E. 


FiGUKB  11. — Structure  section  showing  method  of  determining  the  succession  of  folds. 

Penciled  lines  corresponding  to  those  shown  by  dots  in  figure  11 
should  be  carefully  added  in  redrawing  a  roughly  sketched  section 
that  shows  complex  folding.  An  original  indefinite  sketch  that  shows 
complicated  structure  affords  opportunities  for  error  in  preparing 
the  new  drawing,  and  omissions  may  be  detected  by  following  the 
formations  as  they  would  be  continued  above  and  below  the  section, 
as  shown  by  the  dotted  lines  in  the  figure. 

PLANS   AND   CROSS   SECTIONS   OF  MINES. 

Plans  of  mines,  like  diagrams,  should  not  be  elaborate,  and  their 
lettering  should  be  plain  and  legible,  yet  it  should  not  be  so  con- 
spicuous as  to  obscure  other  details.  Gothic  letters  should  generally 
be  used,  but  some  plans  require  different  styles  of  lettering,  espe- 
cially for  geographic  or  other  names  that  should  be  coordinate  with 
those  on  maps  or  other  illustrations  in  the  book.  Unless  there  are 
good  reasons,  however,  for  varying  the  styles  of  lettering,  plain 


66  PRErARATIOX  OF  ILLUSTRATIONS. 

c:othic  capitals,  or  capitals  and  lower-case  letters,  either  upright  or 
slanting,  should  be  used.  Abbreviations  for  the  numbers  of  levels 
should  generally  be  given  thus :  3d  level,  6th  level,  200-foot  level,  etc.^ 
or  the  shorter  terms  may  be  spelled  out,  as  third  level,  sixth  level. 
The  same  general  scheme  of  lettering  should  be  used  on  all  plans  and 
cross  sections  that  are  to  appear  in  one  publication  or  in  one  series  of 
similar  papers. 

The  reduction  of  such  drawings  to  the  minimum  scale  consistent 
with  clearness  is  always  advisable. 

DRAWINGS  OF  SPECIMENS  OF  ROCKS  AND  FOSSILS. 

METHODS  USED. 

Drawings  of  specimens  or  other  objects  were  once  made  with 
brush  and  pencil  or  with  pen  and  ink,  by  means  of  measurements 
taken  with  dividers  or  by  viewing  the  specimen  througli  a  camera 
lucida.  Each  of  these  methods  is  still  used,  but  by  using  the  camera 
lucida  in  sketching  the  outlines  and  details  more  accurate  propor- 
tions and  relations  can  be  produced,  whether  the  object  is  to  be  en- 
larged or  reduced,  than  by  any  other  means  except  photography. 

BRUSH  AND  PENCIL  DRAWINGS. 

In  all  drawings  or  photographs  of  specimens,  except  photomicro-" 
graphs  of  thin  sections,  the  light  should  appear  to  come  from  the 
upper  left  quarter.  A  disregard  of  the  well-established  rule  tliat  the 
direction  of  illumination  should  be  uniform  throughout  a  series  of 
drawings  would  cause  confusion  or  uncertainty  in  the  interpretation 
of  the  relief  shown  in  them. 

Eeynolds's  three-ply  and  four-ply  bristol  board  affords  a  satisfac- 
torj  surface  for  brush  and  pencil  drawings.  Its  surface  is  smooth 
and  hard  and,  being  free  from  coating  of  any  kind,  permits  satis- 
factory erasures  without  great  injury;  its  color  is  pure  white;  and  it 
is  durable. 

Ross's  relief  hand-stipple  paper  is  also  well  adapted  to  many  kinds 
of  brush  drawings  as  well  as  to  its  primary  use  for  producing  stippled 
effects.  Very  delicate  gradations  of  color  or  light  and  shade  can  be 
produced  on  its  surface  witli  brush  and  lampblack  or  with  india  ink, 
and  high  lights  can  be  made  by  scraping  off  the  chalky  surface. 

The  draftsman  who  is  preparing  brush  and  pencil  drawings 
should  have  first  of  all  a  knowledge  of  the  principles  of  light  and 
shade,  of  reflected  light,  and  (for  draAving  specimens)  of  shadow 
perspective.  He  should  also  have  delicacy  of  touch  and  ability  to 
see  and  interpret  form  and  to  reproduce  the  soft  blending  of  light 
and  shade  shown  in  a  good  photograph.  He  should  be  provided 
with  pencils  equal  in  quality  to  the  Koh-i-noor  B.  F,  4H,  and  611; 


PREPARATIOIT   OF  ILLUSTRATION'S.  67 

the  best  quality  of  red  sable  brushes  of  the  sizes  of  Winsor  &  Newton's 
Nos.  3,  4,  and  6 ;  the  best  quality  of  stick  india  ink ;  a  cake  or  pan  of 
lampblack ;  and  a  porcelain  saucer  or  slab. 

In  drawings  of  fossils  and  of  some  other  specimens  a  combination 
of  pencU  and  brush  work  produces  satisfactory  results  and  tends  to 
increase  speed.  The  gloss  produced  by  penciling,  however,  is  objec- 
tionable and  should  be  obviated  by  a  preponderance  of  brush  work. 
Stick  India  ink  is  the  best  pigment  to  use  in  delicate  wash  draw- 
ings, and  lampblack  is  preferable  for  large  work  on  which  the  softer 
tones  of  the  shading  are  not  so  important  and  for  drawings  that  are  to 
be  considerably  reduced  when  engraved.  Gouache  (an  opaque  mixture 
of  Chinese  white  and  lampblack)  may  also  be  used,  but  it  is  best 
suited  for  large  work. 

In  making  corrections  on  brush  drawings  the  parts  to  be  corrected 
should  be  carefully  washed  out  with  a  small  short-cropped  brush 
and  water  and  still  further  cleaned  by  using  a  rubber  eraser  over 
an  erasing  shield  or  an  opening  cut  in  a  piece  of  celluloid.  Erasures 
should  not  be  made  on  delicate  work  with  a  knife  or  a  sand  rubber, 
as  either  will  injure  the  surface  and  affect  reproduction.  In  meas- 
uring a  specimen  with  dividers  the  draftsman  should  be  careful  not 
to  injure  the  specimen  or  to  puncture  the  paper  on  which  he  is  pre- 
paring the  drawing. 

PEN  DRAWINGS. 

A  draftsman  who  is  preparing  drawings  of  specimens  with  pen 
and  ink  should  have  a  good  assortment  of  pens  equal  to  Gillott's  Nos. 
291,  290,  and  170,  liquid  waterproof  ink  equal  to  that  manufactured 
by  Higgins,  good  pencils,  hard  and  soft  rubber  erasures,  plain  di- 
viders, and  Reynolds's  bristol  board.    A  glass  eraser  is  also  useful. 

Good  pen  drawings  of  specimens  are  much  more  difficult  to  make 
than  brush  drawings.  They  can  be  prepared  only  by  a  draftsman 
who  has  had  some  artistic  training  and  experience  in  pen  work.  Few 
draftsmen  can  prepare  pen  drawings  that  faithfully  represent  both 
the  detail  and  the  texture  of  specimens;  the  shading  on  many  such 
drawings  confuses  and  destroys  both  detail  and  texture. 

The  pencil  sketch  over  which  a  pen  drawing  of  a  specimen  should 
be  made  must  be  prepared  in  much  the  same  manner  as  the  sketch 
for  a  brush  drawing,  though  the  outlines  need  not  be  so  delicate. 
This  sketch  is  generally  made  on  bristol  board.  The  pen  work 
should  begin  with  the  outlines  and  should  then  be  carried  to  the  de- 
tails, and  finally  to  the  shading,  whether  in  lines  or  stipple.  The 
texture  of  a  specimen  is  the  best  key  to  the  proper  shading.  If  the 
specimen  is  decidedly  granular,  stippling  is  appropriate;  if  it  is 
smooth  or  polished,  finely  drawn  parallel  lines,  varied  in  spacing  and 
character  according  to  depth  of  shade  and  texture,  are  preferable. 


68  PREPARATION   OF  ILLUSTRATIOISTS. 

Erasures  can  be  made  with  a  hard-rubber  eraser,  other  parts  being 
protected  by  a  shield,  or  with  a  very  sharp  knife  or  a  glass  eraser,  and 
the  parts  erased  can  be  resurfaced  with  an  agate  burnisher. 

RETOUCHING   PHOTOGRAPHS    OF    SPECIMENS. 

Photographs  of  sj^ecimens,  particularly  fossils  that  have  been 
coated  to  destroy  local  color,  should  be  printed  on  velox  paper,  in 
a  tone  somewhat  lighter  than  that  of  ordinaiy  photographs.  The  de- 
tails and  relief  should,  however,  be  strong  enough  to  enable  the 
draftsman  to  see  them  clearly,  so  that  by  retouching  them  and 
strengthening  the  shadows  and  high  lights  he  can  make  them  suffi- 
ciently strong  for  reproduction.  This  he  can  do  by  a  combination  of 
pencil  and  brush  work,  the  pencil  being  used  sparingly  because  the 
gloss  produced  by  the  graphite  is  likely  to  affect  reproduction.  A 
No.  3  Winsor  &  Newton's  red  sable  brush  and  lampblack  are  preferable 
for  the  greater  part  of  this  work,  and  a  4H  and  a  6H  pencil  for  the 
fine  details  and  as  a  possible  aid  in  producing  the  finer  gradations 
of  shading.  The  details  should  be  retouched  or  strengthened  under  a 
reading  glass  to  insure  accuracy ;  the  broader  effects  can  be  best  pro- 
duced without  the  aid  of  a  magnifier. 

Erasures  on  photographs  of  specimens  should  be  made  very  care- 
fully with  a  hard  rubber  that  is  free  from  sand,  and  the  parts  not  to 
be  disturbed  should  be  protected  with  a  shield.  High  lights  may  be 
added  by  carefully  scraping  or  rubbing  the  surface  of  the  paper. 

IjANdscape  drawings  from  poor  photographs. 

A  poor  photograph  or  one  that  has  become  injured  and  can  not 
be  retouched  for  direct  reproduction  can  be  utilized  by  making  from 
it,  as  described  below,  a  pen  drawing  or  a  brush  or  crayon  drawing, 
which  will  be  almost  photographically  correct. 

PEN  DRAWINGS  MADE  OVER  PHOTOGRAPHS. 

A  pen  and  ink  drawing  may  be  made  over  a  blue  print  or  a  bromide 
print  (preferably  a  blue  print)  and  the  photographic  image  then 
bleached  out.  The  blue  print  should  be  larger  than  publication  size 
and  should  not  be  so  dark  that  the  draftsman  can  not  see  his  lines. 
If  the  negative  is  available  a  bromide  enlargement  can  be  obtained ; 
otherwise  the  picture  should  be  rephotographed  in  larger  size,  pref- 
erably twice  publication  size.  The  enlargement  will  give  the  drafts- 
man greater  freedom  in  drawing  details  and  will  make  his  work  ap- 
pear finer  and  better  in  the  reduced  illustration.  If  the  photographic 
prmt  is  of  a  subject  requiring  the  use  of  instruments  it  should  be 
securely  fastened  to  a  drawing  board,  square  with  the  board,  so  that 
any  horizontal  and  vertical  lines  in  it  may  be  ruled  by  the  use  of  a 


PREPARATION  OF  ILLUSTRATION'S.  69 

T  square  and  triangle.    For  specimen  or  landscape  work  it  need  not 
be  fastened. 

For  bleaching  blue  prints  a  saturated  solution  of  oxalate  of  potas- 
sium (K2C0O4+H2O)  has  been  used  with  good  results.  For  bleach- 
ing bromide  prints  cyanide  of  potassium  (KCN)  to  which  a  few 
drops  or  Jflakes  of  iodine  have  been  added  should  be  used.  Neither 
kind  of  print  should  be  bleached  until  the  drawing  has  been  com- 
pletely finished  in  every  detail,  because  bleaching  loosens  the  fibers 
of  the  paper,  so  that  the  ink  of  any  added  lines  is  likely  to  spread. 
The  print  should  be  placed  in  a  hard-rubber  pan,  the  bleacliing  solu- 
tion poured  on  it,  and  the  pan  rocked  until  the  image  disappears. 
The  print  should  then  be  carefully  removed,  thoroughly  washed  in 
running  water,  placed  between  clean  white  blotters  to  dry,  and 
finally  mounted  on  cardboard.  For  temporary,  hurried  work  on 
drawings  that  are  not  to  be  retained  for  future  use  the  blue  print  may 
be  mounted  first  and  bleached  by  pouring  the  bleaching  fluid  over  the 
mounted  print. 

BRUSH  DRAWINGS  FROM  POOR  PHOTOGRAPHS. 

Brush  drawings  may  be  made  directly  from  photographs  by  work- 
ing over  an  enlarged  print  with  gouache,  or  by  making  a  pencil 
tracing  and  sketch  of  the  photogi'aph  and  working  it  up  with  lamp- 
black or  india  ink.  The  photograph  should  be  larger  than  publica- 
tion size  to  permit  greater  freedom  and  breadth  in  drawing  details. 
The  larger  size  will  also  afford  a  more  refined  and  better  engi'aving 
when  reduced.  If  lampblack  or  india  ink  is  used  and  the  subject  is 
small,  bristol  board  is  recommended,  but  if  the  photograph  is  larger 
than,  say,  8  by  10  inches,  Whatman's  hot-pressed  double  elephant  or 
similar  paper,  laid  down  with  thumb  tacks,  will  prove  satisfactory. 

If  gouache  is  used  over  a  print  a  preliminary  drawing  is  of  course 
unnecessary,  but  the  photograph  should  be  an  unglazed  print  of 
a  size  that  will  require  considerable  reduction,  and  the  finished  draw- 
ing should  be  protected  by  an  oversheet.  If  lampblack  or  india  ink 
and  not  gouache  is  used  the  photograph  should  be  traced  and  a  fairly 
complete  pencil  sketch  should  be  made  before  the  brush  is  used. 

Plates  I,  IV,  ^1,  V,  5,  and  VII,  5,  Monogi-aph  34,  were  made  from 
gouache  drawings.  Plates  III,  A,  VII,  A,  X,  XI,  XII,  XIII,  XX, 
XXVIII,  and  XXX,  in  the  same  publication,  were  made  from  lamp- 
black or  india-ink  wash  drawings.  The  originals  can  be  examined 
at  any  time. 

OUTDOOR  SKETCHES. 

The  art  of  sketching  from  nature  is  one  in  which  few  but  pro- 
fessional artists  excel.  Not  many  geologists  are  able  to  make  sketches 
from  nature  that  are  suitable  foi-  direct  reproduction.  An  artistic 
draftsman  should  be  able  to  redraw  the  geologist's  sketches,  however, 


70  PREPAEATION    OF   ILLUSTRATIONS. 

in  their  true  perspective  and  relations,  with  the  skill  necessary  to 
make  them  satisfactoiy  illustrations. 

In  most  crude  outdoor  sketches  the  important  features  are  usually 
shown  with  sufficient  clearness  to  follow.  If  they  are  not  the  drafts- 
man should  ascertain  what  those  features  are  and  prepare  the  new 
drawing  in  such  a  way  as  to  display  them  properly.  The  new  draw- 
ing should  be  made  with  pen  and  ink,  generally  for  reduction  to  a 
text  figure,  which  is  the  most  appropriate  form  for  such  an  illustration. 

In  all  sketches  of  this  kind  the  lines  should  be  drawn  in  such  a 
way  as  to  produce  natural  effects  and  at  tjie  same  time  to  make  good 
printing  plates.  Good  examples  of  pen  and  ink  sketches  of  this 
class  can  be  found  in  Monograph  34,  already  referred  to,  and  in  the 
Seventh  Annual  Report,  especially  Plates  XXVIII  and  XXXVIII ; 
Ninth  Annual  Report,  Plates  XLIII  and  XLIV;  Tenth  Annual  Re- 
port, Plates  XIV  and  XIX  and  figure  58 ;  Eleventh  Annual  Report, 
Plates  XV,  XXVII,  XXXV,  LII,  and  LIV  and  figures  18,  30,  31,  67, 
98,  and  99. 

DRAWINGS    OF   CRYSTALS. 

A  crystal  should  generally  be  drawn  in  outline  with  straight  lines. 
The  invisible  rear  side  of  a  crystal,  if  shown,  should  be  represented  by 
dashed  lines.  The  outer  boundary  line  of  a  crystal  should  be  slightly 
heavier  than  the  inside  lines,  which  should  all  be  of  the  same  weight. 
Striations  should  be  shown  by  straight  lines ;  broken  or  uneven  sur- 
faces by  irregular  lines.  A  twinning  line,  if  an  intersection  edge, 
should  be  solid ;  if  not  an  intersection  edge  it  should  be  broken  into 
dashes.  Italic,  Greek,  German,  and  Old  English  letters  are  used  to 
mark  cr^^stal  faces.  All  faces  of  a  given  form  should  be  marked  by 
the  same  letter  but  may  be  differentiated,  if  necessary,  by  primes  or 
numerals,  thus:  m,  m',  m",  m"',  m^^  "Leaders"  should  be  short 
full  lines,  or,  if  these  are  likely  to  be  confusing,  they  should  be  dashes. 
Numbers  may  be  used  in  place  of  letter's  for  specific  purposes.  Let- 
ters indicating  twin  faces  are  underscored;  a  second  twin  is  doubly 
underscored  or  overscored,  thus :  m,  m,  m.  Twin  units  may  be  differ- 
entiated by  the  use  of  roman  numerals. 

RETOUCHING   PHOTOGRAPHS. 

An  author,  of  course,  selects  his  photographs  to  illustrate  some 
special  features;  he  does  not  always  consider  their  fitness  for  repro- 
duction. Photographs  that  are  blurred  or  out  of  focus,  those  in 
which  the  shadows  arc  too  black  or  lack  transparency,  and  those 
which  have  local  defects,  such  as  bad  skies  or  spots,  must  be  worked 
over  to  make  them  suitable  for  reproduction.  In  order  to  remedy 
these  defects  and  produce  natural  results  the  draftsman  doing  work 
of  this  sort  should  be  able  to  see  and  interpret  nature  properly  and 


PREPAKATION  OF  ILLUSTRATIONS.  71 

to  supply  natural  effects  in  a  manner  corresponding  with  those  pro- 
duced photographically.  He  should  be  sufficiently  expert  with  the 
brush  and  pencil  and  in  handling  an  air  brush  to  duplicate  the  delicate 
and  soft  tones  in  the  photograph,  and  he  should  know  how  the  pig- 
ments he  uses  will  "  take  "  when  the  subject  is  reproduced. 

The  retoucher  should  have  access  to  an  air  brush  and  should  pro- 
vide himself  with  a  jar  of  photo  white  or  blanc  d'argent  and  a  color 
box  containing  Indian  red,  crimson  lake,  yellow  ocher,  lampblack,  and 
ultramarine — colors  with  which  he  can  duplicate  those  shown  in  any 
photograph.  He  should  also  have  the  best  grade  of  red  sable  brushes, 
ranging  in  size  from  No.  3  to  No.  8,  a  stack  of  porcelain  saucers,  and 
a  jar  of  oxgall.  By  mixing  the  colors  to  match  exactly  the  shades 
of  a  photograph  and  using  a  red  sable  brush  he  can  strengthen  de- 
tails, "spot  out"  flaws,  and  remove  imperfections,  except  those  in- 
sldes  or  other  large,  flat  areas,  for  which  he  must  use  an  air  brush. 

The  air  brush  has  become  a  necessary  adjunct  to  a  retoucher's  out- 
fit. Smooth,  even  gradations  of  flat  tones  can  not  be  successfully 
applied  to  photographs  without  it,  and  it  is  therefore  indispensable, 
especially  for  retouching  skies  and  covering  other  large  areas. 

Before  retouching  a  photogi^aph  the  draftsman  should  mix  in  a 
saucer  a  tint  tliat  will  match  the  color  of  the  part  that  is  to  be  re- 
touched and  should  try  this  tint  and  note  its  effect  after  it  has  dried 
and  change  it,  if  necessary,  until  it  matches  the  color  exactly.  If  he 
is  to  retouch  a  number  of  photographs  that  have  the  same  local  color 
he  may  with  advantage  make  up  enough  of  the  tint  for  the  entire 
lot,  thoroughly  mixing  it  and  seeing  that  it  is  not  too  thin.  In  mak- 
ing this  tint  he  should  use  only  pigments  of  the  best  grade,  and  if 
he  finds  that  the  Chinese  or  other  white  he  is  using  does  not  photo- 
graph well,  or  that  it  does  not  hold  its  color,  he  should  discard 
it  at  once  and  use  another  brand.  Photographs  that  are  to  be  re- 
touched should  be  large  enough  to  permit  sufficient  reduction  to 
soften  the  effects  of  retouching. 

In  order  to  eliminate  the  lines  of  junction  between  two  or  more 
photographs  that  are  joined  together  to  form  a  panorama  some  ad- 
justment or  fitting  of  details  by  retouching  is  generally  required 
before  the  group  is  rephotographed  to  obtain  a  new  print  of  the  whole 
on  one  piece  of  paper.  As  it  is  often  desirable  to  increase  the  width 
of  such  an  illustration  the  photographer  should  be  instructed  to  print 
the  photograph  on  a  strip  of  paper  that  is  wider  than  the  negative,  so 
that,  if  necessary,  the  retouching  may  be  carried  above  or  below  the 
new  print  to  add  depth  to  the  illustration. 

Panoramas  may  also  be  drawn  from  photogi-aphs  with  either  pen 
or  brush  in  the  manner  described  on  pages  68-69. 

801754° — -19 6 


PART  III.   PROCESSES   OF   REPRODUCING   ILLUSTRA- 

TIONS. 

METHODS  EMPLOYED. 

The  preliminary  work  in  producing  illustrations  includes  the 
preparation,  from  originals  submitted  by  authors,  of  drawings  and 
other  kinds  of  "  copy  "  in  such  a  way  that  the  copy  can  be  reproduced 
in  multiple  by  printing. 

Several  processes  are  used  for  preparing  plates  for  printing  illus- 
trations, and  each  has  its  peculiar  features  of  excellence.  One  proc- 
ess may  render  fine  details  with  facility  but  may  fail  in  uniformity 
in  large  editions;  another  may  be  cheap  and  ejffective  on  the  whole 
but  may  not  reproduce  fine  details;  and  still  another  may  give  fine 
color  or  tone  effects  but  may  be  too  expensive.  Therefore  a  knowl- 
edge of  the  varied  uses  and  results  and  of  the  cost  of  the  several 
processes  of  reproduction  and,  on  the  other  hand,  of  the  kinds  of 
originals  that  are  best  suited  for  reproduction  by  any  one  of  the 
processes  is  essential  to  effectiveness  and  economy  in  planning,  pre- 
paring, and  reproducing  an  illustration. 

The  following  condensed  descriptions  of  processes  are  intended 
mainly  to  aid  in  determining  the  kind  of  copy  that  is  appropriate 
for  each  process  and  the  kind  and  quality  of  reproduction  to  be  ex- 
pected, so  that  only  the  principal  operations  or  stages  in  each  process 
are  described.  Wood  engraving,  which  was  used  in  making  printing 
plates  for  many  of  the  illustrations  in  the  early  publications  of  the 
Geological  Survey,  is  described  here  only  to  compare  that  laborious 
and  "  indirect "  method  of  engraving  cuts  with  the  more  modern 
kinds  of  relief  engraving.    In  1892  it  gave  way  to  photo-engraving. 

PHOTO-ENGRAVING. 

GENERAL  FEATURES. 

The  term  "  photo-engraving  "  is  applied  to  processes  by  which  a 
black  and  white  line  drawing,  photograph,  or  like  original  is  repro- 
duced in  relief  on  a  metal  plate  from  wliich  prints  may  be  made  on 
an  ordinary  printing  press,  in  distinction  from  processes  that  print 
from  flat  or  relatively  flat  surfaces,  such  as  the  lithographic  and 
photogelatin  processes.  The  photo-engraving  processes  that  are  most 
generally  used  are  those  called  "zinc  etching"  and  "half-tone  en- 
graving." These  processes  depend  on  the  discovery  that  gelatin  or 
72 


PREPARATION  OF  ILLUSTRATIONS.  73 

similar  organic  material,  if  treated  with  potassium  or  ammonium 
bichromate  and  exposed  to  the  action  of  light,  is  made  insoluble  in 
water.  If  a  metal  plate  coated  with  bichromatized  gelatin  or  albu- 
men is  exposed  to  light  under  a  negative  the  parts  acted  upon  by 
light  become  insoluble  and  those  not  acted  upon  remain  unchanged 
and  may  be  washed  away  so  as  to  expose  the  metal,  which  is  then 
etched  with  acid  in  order  to  give  relief  to  the  unexposed  parts  and 
make  of  them  a  printing  surface. 

ZINC   ETCHING. 

Zinc  etching  is  adapted  to  the  direct  reproduction  of  a  pen  and 
ink  drawing  composed  of  lines,  dots,  or  solid  black  areas.  On  the 
finished  metal  plate  these  lines,  dots,  and  solid  areas  form  the  print- 
ing surface,  and  the  spaces  between  them,  which  have  been  etched 
away,  represent  the  white  or  blank  parts  of  the  picture.  The  process 
is  cheap  and  is  almost  universally  used  for  reproducing  small  draw- 
ings designed  for  text  illustrations.  It  is  also  well  adapted  to  the 
reproduction  of  maps  and  diagi"ams  measuring  in  print  not  more 
than  about  10  by  14  inches.  One  of  the  chief  advantages  of  this  and 
of  all  other  direct  (photographic)  processes  of  engraving  is  that 
they  reproduce  a  drawing  in  facsimile,  whereas  the  "  personal  equa- 
tion "  must  enter  into  all  engravings  made  by  an  indirect  method — 
that  is,  by  hand — such  as  wood  engi'aving,  wax  engraving,  and  en- 
graving on  stone  or  copper,  which  make  it  necessary  to  compare 
every  detail  of  the  proof  with  every  detail  of  the  drawing  before 
the  engraving  can  be  approved.  The  pen  drawing  to  be  reproduced, 
which  should  preferably  be  considerably  larger  than  the  completed 
engraving,  is  first  photographed  to  the  proper  size  or  scale  on  an 
ordinary  negative  film.  The  film  is  then  stripped  from  the  negative 
and  reversed  in  order  that  the  etched  plate  may  print  the  design  as 
in  the  original  and  that  the  film  may  be  grouped  with  other  fihns  on 
one  large  glass  and  all  printed  at  the  same  time.  The  negative 
(whether  a  single  film  or  several)  is  then  placed  in  a  specially  con- 
structed printing  frame  in  contact  under  pressure  with  a  sensitized 
zinc  plate  and  exposed  to  light. 

After  the  zinc  plate  has  been  removed  from  the  printing  frame 
(in  the  dark  room)  the  plate  is  rolled  with  printer's  transfer  ink, 
which  resists  acid,  and  placed  in  a  shallow  tray  containing  water,  in 
which  it  is  rocked  for  several  minutes,  and  then  taken  out  and  rubbed 
gently  with  cotton.  The  parts  of  the  coating  of  the  plate  that  were 
acted  on  by  light  have  become  insoluble  and  will  therefore  be  un- 
affected by  the  water,  but  the  parts  of  the  coating  not  acted  on  by 
light  and  therefore  not  hardened  will  be  removed  by  the  washing, 
which  will  expose  the  metal  and  leave  the  parts  acted  on  by  light — 


74  PREPARATION   OF   ILX,USTRATIONS. 

the  jjictuie — in  black  lines,  dots,  etc.  The  plate  is  then  dusted  with 
"topping  powder,"  a  resinous  substance  which  adheres  only  to  the 
parts  carrying  the  ink.  The  plate  is  then  heated  so  that  the  resin 
and  the  ink  that  remain  fuse  together  and  form,  when  cooled,  a 
resistant  surface  which  will  not  be  affected  by  the  acid  to  be  used 
later  in  etching  the  unprotected  parts  of  the  plate. 

Thb  plate  is  now  ready  for  a  preliminary  etching  in  a  fluid  consist- 
ing of  water  and  a  few  drops  of  nitric  acid.  It  is  placed  in  a  tray, 
rocked  gently  for  a  short  time,  and  then  removed,  washed  well  in 
running  water,  drained,  and  dried  with  gentle  heat.  "  Dragon's 
blood,"  a  resinous  powder  that  resists  the  action  of  acid,  is  next 
applied  to  the  plate,  in  order  to  protect  the  sides  of  the  lines  and  the 
dots  from  the  acid,  and  the  plate  is  then  heated  just  sufficiently  to 
melt  the  powder  and  unite  it  with  the  ink.  A  small  quantity  of 
nitric  acid  is  now  added  to  the  etching  bath,  and  the  plate  is  sub- 
jected to  its  first  thorough  biting  or  etching.  It  is  then  removed 
from  the  bath,  washed  under  a  tap,  carefully  wiped  with  a  damp  rag, 
and  dried  with  gentle  heat. 

The  plate  is  thus  treated  three  or  more  times  until  it  is  etched  deep 
enough  to  insure  satisfactory  printing,  and  it  is  then  ready  for 
finishing,  which  consists  of  deepening  the  larger  open  spaces  between 
the  lines  with  a  routing  machine  and  of  cutting  away  with  hand 
gravers  lines  that  are  improperly  connected  or  that  are  so  close 
together  that  they  will  not  print  separately.  The  routing  machine 
is  provided  with  a  cutting  tool  mounted  on  a  revolving  spindle  that 
projects  downward  into  the  engraved  plate,  which  is  securely 
fastened.  The  movement  of  the  arm  that  holds  the  cutter  is  universal 
and  can  be  controlled  with  great  precision.  The  plate  is  then 
"proved" — that  is,  a  proof  is  taken  from  it  on  paper — and  if  the 
proof  is  satisfactory  the  plate  is  nailed  to  a  block  of  wood  on  which  it 
will  be  "  type  high  "  (0.918  inch) ,  for  printing. 

Most  drawings  for  zinc  etching  are  made  with  a  pen  in  black 
ink  and  consist  of  lines,  dots,  or  masses  of  black,  but  drawings  may 
also  be  prepared  by  using  some  medium  that  will  produce  a  fine 
stipple,  such  as  a  black  crayon  on  rough  paper  or  Ross's  stipple  paper. 
(See  p.  24.)  The  drawing  should  be  one  and  one-half  to  two  or 
three  times  as  large  as  the  printed  illustration,  for  it  is  impossible 
to  obtain  a  satisfactory  reproduction  of  a  pen  and  ink  drawing  with- 
out some  reduction.  If  the  drawing  has  not  been  reduced  the  lines 
appear  heavier  in  the  reproduction  than  in  the  drawing,  and  imper- 
fections thus  become  more  noticeable;  if  it  has  been  properly  reduced, 
imperfections  are  diminished  and  the  lines  and  dots  become  thinner 
and  finer  than  those  in  the  drawing.  In  making  a  drawing  that  is  to 
be  reduced  the  draftsman  can  also  space  his  lines  farther  apart  and 
work  out  his  details  more  easily. 


PREPAKATION  OF  ILLUSTRATIONS.  75 

An  author  should  carefully  examine  and  approve  the  finished 
drawings,  which  can,  of  course,  be  greatly  altered,  if  necessary, 
before  they  are  engraved ;  but  similar  corrections  can  not  be  made  on 
proof  sheets  of  zinc  cuts,  which  should  not  be  marked  for  alterations 
except  by  eliminating  parts.  Minor  changes  can  be  made  in  such 
a  cut  by  an  expert  "  finisher,"  but  if  the  cut  is  small  it  is  generally 
cheaper  to  correct  the  drawing  and  have  a  new  cut  made. 

Zinc  etchings  cost  about  10  to  25  cents  a  square  inch,  the  cost  being 
varied  according  to  a  standard  scale  which  is  based  upon  the  ascer- 
tained cost  of  reproduction.  The  minimum  charge  for  a  single  cut 
is  $2. 

COPPER  ETCHING  IN  RELIEF. 

Copper  etching,  which  produces  a  line  cut  in  relief,  requires  the 
same  kind  of  copy  that  is  most  often  marked  for  zinc  etching  and  is 
used  to  obtain  deeper  etching  and  a  more  permanent  cut.  It  is  said 
to  produce  better  printing  plates  than  those  etched  on  zinc  and  is 
used  largely  for  reproducing  script  lettering  and  other  fine  work. 
As  copper  plates  will  hold  up  longer  in  printing  than  zinc,  a  cut 
■etched  on  copper  may  not  need  to  be  electrotyped. 

The  chemical  part  of  the  process  is  practically  the  same  as  that 
employed  for  etching  half-tone  plates,  described  under  the  next 
heading. 

The  cost  of  etching  on  copper  is  considerably  greater  than  the  cost 
of  etching  on  zinc.  This  process  is  not  often  used  in  reproducing 
illustrations  for  publications  of  the  Geological  Survey. 

HALF-TONE  ENGRAVING. 

The  half-tone  process  is,  in  name  at  least,  familiar  to  almost  every- 
one who  has  had  any  connection  with  the  making  of  books,  whether 
as  author,  editor,  illustrator,  or  printer.  The  invention  of  a  photo- 
mechanical process  of  reproducing  a  line  drawing  to  make  a  metal 
plate  that  could  be  printed  along  with  type  on  an  ordinary  printing 
press  naturally  led  to  attempts  to  reproduce  similarly  a  photograph. 
It  was  known  that  the  intermediate  shades  between  white  and  black 
in  a  photograph — ^the  half  tones — can  be  reproduced  on  an  ordinary 
printing  press  only  by  breaking  them  up  into  dots  or  lines  that  will 
form  a  good  printing  surface  and  that  by  their  variation  in  size  or 
density  will  give  for  each  shade  the  effect  of  a  uniform  tone.  In 
the  half-tone  process  this  effect  is  produced  by  photographing  the 
picture  or  object  tlirough  a  screen. 

The  half-tone  screen  consists  of  two  plates  of  glass,  on  each  of 
which  lines  running  generally  at  an  angle  of  45°  to  the  sides  of  the 
plate  have  been  engraved,  cemented  together  so  that  the  lines  cross 
at  right  angles.    The  lines,  which  are  minute  grooves  filled  with  an 


76  PREPAEATION   OF  ILLUSTRATIONS. 

opaque  black  pigment,  thus  appear  as  a  series  of  black  crossed  lines 
on  a  white  ground.  The  screen  is  placed  in  the  camera  in  front  of 
the  negative.  Screens  are  made  that  show  from  50  lines  to  an  inch 
for  the  coarser  newspaper  illustrations  to  250  lines  or  more  to  the 
inch  for  fine  book  work.  The  screens  used  for  magazine  illustrations 
generally  show  120  to  150  lines.  Those  used  for  Survey  publications 
show  150  to  175  lines,  and  for  reproducing  delicate  drawings  and 
photographs  of  fossils  screens  bearing  200  lines  to  the  inch  are  some- 
times specified ;  but  these  finer  screens  require  the  use  of  highly  super- 
coated  papers,  some  of  them  made  of  cheap  fiber  and  not  known  to 
be  perm  ment.  For  a  half  tone  that  is  to  be  printed  in  the  text  a 
100-line  or  a  120-line  screen  is  specified.     (See  PI.  VI,  p.  56.) 

The  method  of  etching  a  half-tone  plate  does  not  differ  greatly 
from  that  used  in  zinc  etching,  and  there  are  several  kinds  of  half- 
tone plates,  though  most  of  them  are  etched  on  copper,  not  on  zinc, 
those  etched  on  zinc  being  used  principally  for  newspaper  illustra- 
tions. The  half-tone  screen  is  used  also  in  other  processes  to  obtain 
a  negative. 

When  a  half-tone  negative  has  been  made  the  film  is  stripped  from 
the  glass  plate  and  reversed,  as  in  the  zinc-etching  process,  though 
some  half-tone  engravers  use  a  mirror  box  or  prism  by  which  the  pic- 
ture is  so  disposed  on  the  negative  that  it  does  not  need  stripping  and 
reversing.  A  perfectly  flat,  clean,  and  highly  polished  copper  plate, 
generally  large  enough  to  accommodate  several  such  films,  is  then 
coated  with  a  sensitive  film  according  to  one  of  several  formulas,  all 
based  on  the  fact  that  gelatin  or  some  similar  body,  if  sensitized  with 
certain  chromic  salts,  becomes  hardened  and  insoluble  in  water  on 
exposure  to  light.  This  plate  is  then  placed  in  the  printing  frame  in 
contact,  under  pressure,  with  the  glass  negative  plate  and  is  exposed 
to  light  in  the  usual  manner.  The  copper  plate  is  then  removed  from 
the  frame  in  the  dark  room  and  made  readj^  for  etching. 

For  etching  half-tone  plates  on  copper  a  saturated  solution  of  per- 
chloride  of  iron  is  used  instead  of  the  solution  of  nitric  acid  used  for 
zinc  etching.  The  time  of  etching  ranges  from  about  5  to  15  minutes, 
according  to  the  strength  of  the  solution.  One  etching  is  generally 
sufficient,  but  it  may  be  necessary  to  give  the  plate  another  "  biting  " 
if  it  has  not  been  etched  deep  enough,  or  to  re-etch  it  in  order  to 
strengthen  contrasts.  If,  for  instance,  the  sky  in  a  half-tone  plate 
shows  too  dark  or  is  uneven  in  tint  it  can  be  made  lighter  or  more 
even  by  re-etching.  On  the  other  hand,  if  certi\in  features  on  a 
plate  are  too  light  they  can  be  darkened  by  burnishing — rub- 
bing the  surface  with  a  highly  polished  steel  burnisher  under  just 
sufficient  pressure  to  riatten  slightly  the  fine  points  that  form  the 
printing  surface  of  the  plate.    When  the  plate  leaves  the  hands  of 


PREPAEATION  OF  ILLUSTRATIONS.  77 

the  etcher  it  is  turned  over  to  the  finisher,  who  with  a  graver  re- 
moves spots  or  any  other  imperfections  that  may  appear  on  it.  Some- 
times a  roulette  is  used  to  lighten  parts,  and  other  tools  are  used  for 
special  purposes. 

After  a  plate  that  shows  two  or  more  pictures  has  been  etched  and 
finished  it  is  divided  by  sawing  them  apart.  Each  one  is  then  put 
into  a  beveling  machine,  where  its  edges  are  trimmed  and  the  usual 
border  is  made,  if  it  is  desired.  The  separate  plates  are  then  ready 
to  be  proved  and  mounted  on  blocks  of  wood  which  make  them  type 
high,  ready  for  printing. 

The  half-tone  process  is  used  almost  exclusively  for  reproducing 
photographs  and  wash  drawings,  though  it  will  produce  a  facsimile 
of  any  kind  of  copy,  such  as  impressions  from  type,  old  manuscripts, 
or  typewriting,  but  a  shade  composed  of  minute  black  dots  will  ap- 
pear over  the  entire  print  and  there  will  be  no  absolutely  white 
areas  unless  they  are  produced  by  routing  the  plate  or  cutting  out 
the  high  lights.  (See  p.  74.)  The  reproduction  of  an  ordinary  out- 
door photograph  requires  very  little  handwork,  except  for  re-etching, 
burnishing,  and  cutting  the  borders.  In  the  reproduction  of  copy 
that  is  made  up  of  separate  parts,  such  as  groups  of  photographs  of 
specimens  that  are  to  appear  on  a  white  ground,  the  half-tone 
"  tint " — or  more  properly  shade — between  and  around  the  several 
figures  must  be  removed  and  numbers  must  be  added.  This  opera- 
tion requires  two  negatives — one  half  tone  and  one  line — and  produces 
what  is  called  a  "  combination  "  plate.  Therefore  the  difference  in  the 
cost  of  making  a  half-tone  cut  from  a  single  photograph  of  a  land- 
scape and  from  a  cut  made  from  "copy"  of  the  same  size  consisting 
of  a  number  of  small  photographs  or  drawings,  to  which  numbers 
or  letters  are  added,  is  considerable  (about  50  per  cent  greater)  and 
depends  upon  the  amount  of  additional  work  involved.  Routing, 
when  needed,  must  be  done  with  extreme  care  lest  the  edges  of  a 
figure  be  marred,  and  this  work  requires  skill  that  can  be  gained 
only  by  experience. 

Copy  for  the  half-tone  process  should  be  as  nearly  perfect  as  pos- 
sible. Only  the  best  photographs  should  be  selected.  Prints  on 
semimat  velox  and  glossy  haloid  papers  are  regarded  as  the  best 
photographic  copy  for  reproduction.  Every  part  of  the  photograph 
or  drawing  should  be  absolutely  clean.  If  any  part  that  should  be 
pure  white  becomes  soiled  or  stained  the  defects  will  be  reproduced. 
If  a  photograph  needs  retouching  it  should  be  retouched  with  great 
care  and  just  sufficiently  to  correct  defects  and  to  bring  out  or 
strengthen  the  important  details.  In  many  photographs  the  skies 
may  be  "  muddy  "  or  uneven  in  tone,  and  this  defect  can  be  corrected 
by  the  use  of  an  air  brush,  the  only  medium  that  will  produce  an 
Almost  even  tone.     As  already  stated,  half-tone  plates  can  be  im- 


78  PFvEPARATION    OF   ILLUSTRATION'S, 

proved  by  re-etching  and  tooling,  but  tooling  tends  to  destroy  the 
effects  of  nature  and  produces  an  artificial  appearance  in  the  print. 
One  who  is  preparing  wash  drawings  for  reproduction  by  the  half- 
tone process  should  remember  that  brush  marks  and  other  inequalities 
of  tone  will  be  reproduced  with  as  much  fidelity  as  other  details. 
Such  drawings  should  therefore  be  made  two  or  three  times  larger 
than  the  engi-aved  cut  in  order  to  subdue  all  unnatural  effects  and  to 
soften  the  general  tones. 

Line  drawings  are  not  generally  suitable  copy  for  the  half-tone 
process,  but  it  is  occasionally  desirable  to  use  that  process  instead  of 
zinc  etching  for  reproducing  a  line  drawing  that  has  been  inexpertly 
prepared  if  the  cost  of  redrawing  would  more  than  offset  the  dif- 
ference in  cost  between  zinc  etching  and  the  more  expensive  half- 
tone process.  In  reproducing  a  pen  drawing  by  half  tone  the  lines 
become  softened  and  represent  the  details  and  shading  only ;  but  the 
pen  drawing  may  be  further  developed  by  brush  work.  Examples 
of  this  tj^pe  of  reproduction  are  Plates  V,  A,  VI,  A,  and  XV,  figure 
10,  and  other  illustrations  in  Survey  Monograph  34. 

Vignetting,  which  consists  of  a  skillfid  grading  off  of  the  edges  of 
a  picture,  as  well  as  extensive  tooling  or  hand  engraving,  is  often 
employed  for  artistic  effect  but  should  be  specified  only  for  excep- 
tional illustrations.  The  plates  made  for  the  Survey  are  either 
"square  trimmed"  or  the  ground  tint  is  entirely  omitted  or  routed 
away;  they  are  not  usually  tooled  or  vignetted. 

Half-tone  cuts  etched  on  copper  cost  20  to  60  cents  a  square  inch, 
the  cost  being  varied  according  to  a  standard  scale  based  on  the 
ascertained  cost  of  reproduction.  Those  that  require  a  screen  finer 
than  150  lines  cost  25  per  cent  additional.  The  minimum  charge  for 
a  single  cut  is  $3. 

Half  tones  etched  on  zinc  (100-line  screen  or  coarser)  cost  25  per 
cent  less  than  those  etched  on  copper. 

THREE-COLOR  HALF-TONE  PROCESS. 

The  three-color  process  is  practically  an  adaptation  of  the  half- 
tone process  to  color  printing  based  on  the  theory  that  all  colors  or 
hues  in  nature  can  be  reproduced  by  combinations  of  three  colors  of 
the  spectrum — red,  blue,  and  yellow.  The  process  differs  from  the 
ordinary  half-tone  process  particularly  in  the  use  of  color  filters  in 
making  the  negatives  and  in  the  character  of  screens  and  diaphragms 
used.  This  process,  like  all  others,  is  worked  somewhat  differently 
in  different  establishments.  In  what  is  called  the  indirect  method, 
the  one  most  commonly  used,  twelve  photographic  operations  are 
necessary  to  produce  one  illustration,  or  the  three  plates  or  cuts  from 
which  one  illustration  is  to  be  reproduced  by  printing.     These  twelve 


PREPARATION  OF  ILLUSTRATIONS,  79 

operations  produce  three  chromatic  negatives,  each  representing  one 
color;  three  transparencies  or  positives,  made  from  the  chromatic 
negatives;  three  half-tone  negati^^es,  made  from  the  positives;  and 
finally  three  contact  prints,  made  on  sensitized  metal  plates.  In 
what  is  called  the  direct  method  the  half-tone  screen  is  placed  in 
front  of  the  photographic  plate  so  that  it  becomes  also  a  half-tone 
negative  from  which  a  print  is  made  on  a  sensitized  metal  plate. 
Thus  the  photographic  operations  in  the  direct  method  are  reduced 
to  six,  but  the  interference  to  the  passage  of  light  offered  by  the 
half-tone  screen  and  by  the  prism  used  to  reverse  the  image  on  the 
negative  lengthens  the  time  of  exposure. 

Unfortunately,  no  pigments  have  been  found  that  can  reproduce 
in  purity  the  colors  of  the  spectrum,  and  to  this  fact  is  due  the 
failure  of  the  process  to  reproduce  exactly  all  the  colors,  tints,  and 
shades  of  an  original.  When  a  drawing  in  black  on  white  paper 
is  photographed  only  the  white  paper  affects  the  negative  film.  The 
transparent  parts  of  the  developed  negative  thus  represent  the  black, 
and  the  opaque  parts,  which  have  been  acted  upon  by  light,  represent 
the  white.  Theoretically,  when  a  chromatic  negative  is  made  for 
the  yellow  plate  a  purple-violet  filter  cuts  out  all  the  yellow  and 
allows  the  red  and  blue  rays  to  affect  the  plate ;  when  a  negative  is 
made  for  the  blue  plate  an  orange  filter  similarly  cuts  out  the  blue  and 
allows  the  yellow  and  red  rays  to  affect  the  plate ;  and  when  a  nega- 
tive is  made  for  the  red  plate  a  green  filter  cuts  out  the  red  and 
permits  the  blue  and  yellow  rays  to  affect  the  plate.  These  color 
filters,  which  are  usually  made  of  transparent  stained  gelatin,  are 
generally  placed  in  front  of  the  lens.  When  printing  plates  like 
those  used  in  the  half-tone  process  have  been  made  from  the  three 
negatives  and  the  plates  have  been  inked  with  yellow,  blue,  and  red 
ink,  respectively,  a  combined  impression  from  them  will  produce  a 
close  approximation  of  the  subject  photographed.  The  colored  inks 
often  used  are  light  yellow,  peacock  or  prussian  blue,  and  bright, 
transparent  crimson. 

The  ordinary  half-tone  screen,  which  bears  lines  cut  at  an  angle  of 
4:5°  to  the  sides  of  the  plate,  is  rectangular,  but  the  screens  used 
for  three-color  work  are  made  circular  in  order  that  they  may  be 
turned  in  the  camera  to  make  the  lines  intersect  at  other  angles,  the 
angles  being  varied  to  avoid  producing  an  undesirable  pattern  or  a 
moire  effect.  Turning  the  screen  also  preyents  the  exact  coincidence 
or  superposition  of  the  red,  blue,  and  yellow  dots,  which  would  pro- 
duce black.  In  other  respects  the  screens  do  not  differ  essentially 
from  those  used  in  ordinary  half-tone  work. 

As  special  experience  is  necessarj^  in  printing  three-color  plates  the 
engraver  generally  delivers  the  printed  illustrations  to  the  purchaser 


80  PEEPAEATION    OF   ILLUSTRATIONS. 

instead  of  the  plates,  which  he  furnishes  for  other  kinds  of  relief 
printing. 

The  copy  for  this  process  may  consist  of  anything  in  color,  such  as 
specimens,  objects,  paintings,  or  properly  colored  photographs.  The 
process  does  not  usually  reproduce  all  the  colors  and  tints  of  an 
original  with  equal  exactness  and  is  not  used  by  the  Survey  for  work 
that  demands  precise  reproduction  of  color,  but  it  is  satisfactory  for 
reproducing  most  colored  drawings,  colored  photographs  of  speci- 
mens, or  the  specimens  themselves  if  they  show  individual  variations 
in  color.  As  the  process  is  entirely  photomechanical  it  gives  more 
scientific  accuracy  in  detail  than  cliromolithography,  in  which  there 
is  much  hand  work,  and  it  is  much  less  expensive.  If  the  colors 
shown  in  proofs  are  not  satisfactory  they  can  be  modified. 

The  four-color  process,  in  which  four  color  plates  are  used,  gives 
a  closer  approximation  of  true  color  values  than  the  three-color  proc- 
ess, and  at  a  comparatively  small  increase  of  cost.  The  additional 
color  used  is  generally  a  neutral  gray  or  black. 

WAX    ENGRAVING    (THE   CEROTYPE   PROCESS). 

The  wax  or  cerotype  process  does  not  require  finished  drawings 
and  is  especially  suitable  for  making  text  illustrations  and  small 
maps,  although  it  may  be  used  also  for  large  work.  For  this  process 
blue  prints,  pencil  sketches,  old  prints,  or  rough  copy  of  any  kind 
may  be  submitted — that  is,  it  is  not  necessary  to  furnish  carefully 
prepared  drawings  in  black  ink,  as  it  would  be  for  photo-engraving, 
for  the  wax  engraver  will  reproduce  in  proper  form  any  illustration 
in  which  the  copy  and  the  instructions  show  what  is  wanted,  just  as 
an  experienced  draftsman  will  make  a  good  drawing  from  the  rough 
original  f  urnislied  by  an  author.  Full  and  clear  instructions  should 
always  be  given,  however,  as  to  the  size  of  the  cut  wanted  and  what 
it  is  to  show. 

In  this  process  a  polished  copper  plate  is  coated  with  a  film  con- 
sisting of  beeswax,  a  whitening  medium,  and  other  ingredients,  and 
the  coating,  which  varies  in  thickness  according  to  the  nature  of  the 
copy,  is  sensitized  as  in  the  ordinary  photographic  processes.  The 
map  or  other  design  to  be  engraved  is  first  photographed  to  publica- 
tion size  and  a  contact  print  is  made  on  the  wax  coating  from  the 
negative.  The  lines  and  other  parts  of  the  photographed  image  are 
then  traced  or  cut  through  the  wax  to  the  copper  plate  with  steel 
tools  and  straightened  or  perfected  by  the  engraver,  but  the  lettering 
is  set  in  printer's  tj'pe,  which  is  pressed  into  the  wax  until  it  also 
touches  the  metal  plate.  After  the  work  of  cutting  through  the  wax 
has  been  completed  the  larger  open  spaces  between  the  lines  are 
"  built  up  "  by  the  addition  of  wax  to  give  greater  depth  to  the  plate, 


PREPAKATION   OF   ILLUSTRATIONS.  81 

SO  that  the  wax  plate  thus  built  up  corresponds  to  an  electrotype 
mold.  The  plate  is  then  dusted  with  powdered  graphite  and  sus- 
pended in  a  solution  containing  copper,  where  by  electrolytic  action  a 
copper  shell  is  formed  over  its  surface.  Wlien  this  shell  is  sufficiently 
thick  it  is  removed  from  the  solution  and  reinforced  on  the  back 
with  metal,  and  proofs  are  taken  from  it.  If  the  proofs  are  satis- 
factory the  plate  is  blocked  type-high. 

Wax-engraved  plates  may  be  used  for  printing  colored  maps  or 
diagrams,  in  which  variations  of  tint  are  produced  by  various  kinds 
of  machine  rulings.  The  effect  of  some  of  the  colors  thus  produced 
is  almost  a  "  flat "  tint,  in  which  a  pattern  can  be  detected  only  by 
close  scrutiny.  Some  color  work  is  printed  from  a  wax  base  plate  in 
combination  with  half-tone  color  plates. 

The  price  of  a  wax  engraving  depends  entirely  on  the  size  of 
the  cut,  the  amount  of  work  involved,  and  the  character  of  the  orig- 
inal copy,  but  it  should  not  exceed  very  much  the  cost  of  a  carefully 
prepared  pen  drawing  plus  the  cost  of  a  zinc  etching  made  from  it. 
Cuts  engraved  by  the  wax  process,  like  zinc  and  half-tone  plates, 
are  delivered  to  the  pjiirchaser.  A  wax  engraving  gives  sharper  lines 
than  a  zinc  etching. 

WOOD   ENGRAVING. 

Wood  engraving  was  once  the  universal  method  of  producing  cuts 
for  illustrations  that  were  designed  to  be  printed  on  an  ordinary 
press.  It  is  said  to  be  the  oldest  of  all  methods  of  engraving  illustra- 
tions. The  engraving  is  made  on  a  block  of  boxwood,  a  very  dense, 
hard  wood  of  a  light-yellow  color.  The  block  is  cut  type-high  across 
the  grain,  and  the  engraving  surface  is  made  perfectly  smooth  by 
rubbing  it  with  pumice  or  other  stone.  When  a  cut  is  to  be  larger 
than  3  or  4  inches  square  the  wood  block  is  made  up  of  pieces  securely 
xiovetailed  or  joined  together  to  prevent  splitting  and  warping.  A 
woodcut  is  not  used  for  printing  but  is  electrotyped  and  the  electro- 
type is  used  in  the  press. 

Originally  the  smoothed  surface  of  the  wood  block  was  coated  with 
prepared  chalk  or  Chinese  white,  and  on  this  coating  a  finished  draw- 
ing was  made  with  a  brush  and  pencil  by  an  illustrator.  According 
to  more  recent  practice  the  surface  of  the  wood  is  covered  with  a 
sensitized  coating,  on  which  the  drawing  or  design  to  be  engraved 
is  photographed.  The  engraver  then,  with  various  kinds  of  gravers 
and  other  tools,  cuts  out  the  parts  of  the  picture  that  are  to  be 
represented  by  white  paper  and  leaves  the  lines,  dots,  and  black  areas 
as  a  printing  surface,  thus  translating  the  shades  and  tints  of  the  pic- 
ture into  a  system  of  linesanddotswhichexactly  duplicate,  in  effect, 
the  details  and  tones  of  the  original  design.    In  order  to  produce  a 


82  PREPAEATION  OF  ILLUSTRATIONS. 

line  eifect  of  an  area  in  which  the  tone  is  intermediate  between  white 
and  black  the  engraver  must  space  his  lines  so  that  one-half  the  area 
will  remain  as  printing  surface  and  the  other  half  as  white  spaces, 
and  he  must  give  character  and  direction  to  his  lines,  so  that,  if  he 
is  skillful,  he  can  reproduce  not  only  the  delicate  tones  but  the 
texture  and  details  of  the  original  picture.  Many  wood  engravers 
became  noted  for  their  artistic  rendering  of  magazine  illustrations, 
of  famous  paintings,  and  of  other  works  of  art. 

The  Survey  began  to  abandon  this  method  of  engraving  in  1884, 
when  the  Sixth  Annual  Report  was  in  press,  substituting  for  it  the 
cheaper  photo-mechanical  processes,  zinc  etching  and  half-tone  en- 
graving, and  entirely  abandoned  its  use  in  1892. 

Many  good  examples  of  wood  engraving  may  be  found  in  the  early 
monographs  and  annual  reports  of  the  Geological  Survey.  Mono- 
graph 2  contains  numerous  examples. 

PHOTOGELATIN  PROCESSES. 

Bichromatized  gelatin  is  used  in  several  photomechanical  processes 
of  reproducing  illustrations,  but  in  the  photogelatin  processes  the 
gelatin  not  only  receives  the  image  by  exposure  to  light  through  a 
negative  but  becomes  a  printing  surface  on  a  plate  from  which  prints 
are  made  somewhat  as  in  lithography.  The  several  photogelatin 
processes  are  much  the  same  as  the  original  collotype  process  and 
are  best  known  by  the  names  collotype,  heliotype,  albertype,  artotype, 
and  the  German  name  lichtdruck. 

In  working  these  processes  a  thick  plate  of  glass,  after  certain  pre- 
liminary treatment,  is  coated  with  sensitized  gelatin.  The  plate  is 
then  placed  in  a  drying  room  or  oven  having  a  temperature  of  120° 
F.,  baked  until  it  is  tlioroughly  dry,  and  allowed  to  cool  gradually. 
The  subject  to  be  reproduced  is  then  photogi\iphed  in  the  usual 
manner,  and  unless  a  prism  or  mirror  box  has  been  used  the  nega- 
tive is  stripped  and  reversed  in  order  to  make  the  print  reproduce 
the  original  in  proper  position.  From  the  negative  a  contact  print 
is  made  on  the  gelatin-coated  plate,  the  parts  or  molecules  of  gelatin 
being  hardened  in  proportion  to  the  amount  of  light  that  affects  them. 
After  the  contact  print  has  been  made  the  gelatin  plate  is  thoroughly 
washed  in  cold  water,  in  order  to  dissolve  and  wash  out  the  bichromate 
and  stop  any  further  action  of  light  on  the  plate,  and  is  then 
thoroughly  dried.  Before  prints  are  made  from  the  gelatin-coated 
plate  Avater  is  flowed  on  it  and  penetrates  different  parts  of  the  gelatin 
according  to  their  hardness.  The  darkest  parts  of  the  picture  will 
correspond  to  the  hardest  and  densest  parts  of  the  gelatin,  which  will 
not  absorb  water;  the  lighter  parts  will  take  up  more  water.  The 
surface    water    is    then    removed    with    a    rubber    straight    edge 


PREPARATION   OF   II.LUSTRATIOlSrS.  83 

and  an  absorbent  roller  and  the  plate  is  ready  for  inking.  The  ink, 
being  greasy,  has  no  affinity  for  water,  and  when  it  is  rolled  over  the 
plate  it  adheres  only  to  the  dry  parts  of  the  gelatin,  and  in  the  press 
is  carried  to  the  paper  in  all  the  lights  and  shades  of  the  illustra- 
tion.    The  plate  is  kept  moist  in  printing. 

The  paper  used  for  printing  from  photogelatin  plates  must  be 
free  from  chemicals  that  will  aifect  the  gelatin.  A  nearly  pure  rag 
paper  is  generally  used. 

The  photogelatin  process  is  well  adapted  to  the  reproduction  of 
paleontologic  drawings,  wash  drawings,  photographs,  photomicro- 
graphs, works  of  art,  old  manuscripts — in  fact,  any  kind  of  subject 
in  which  the  reproduction  of  delicate  lights  and  shades  is  essential. 
If  properly  manipulated  it  has  distinct  advantages  over  the  half- 
tone process  in  that  it  can  reproduce  details  and  light  and  shade 
without  showing  the  effect  of  a  screen  and  without  the  use  of  coated 
paper.  Excellent  reproductions  by  the  heliotype  process  are  also 
made  in  color  by  first  printing  the  design  in  a  neutral  tone  and  super- 
posing appropriate  transparent  colors  on  this  print,  somewhat  as  in 
chromolithography,  so  that  the  colors  softly  blend  with  the  shaded 
groundwork. 

Eeproductions  made  by  the  pliotogelatin  process  are  more  expen- 
sive than  those  made  by  the  half-tone  process,  for  the  prints  are 
generally  made  on  better  paper  and  are  printed  with  greater  care. 
They  give  no  screen  effect  and  are  perhaps  imrivaled  by  prints 
obtained  by  any  other  process  except  photogravure,  in  which  the 
image  is  printed  from  a  metal  plate  that  has  been  sensitized,  exposed 
under  a  reversed  negative,  and  etched. 

Changes  can  not  be  made  on  photogelatin  plates  except  by  making 
over  the  corrected  parts.  All  retouching  must  be  done  on  the  origi- 
nals or  on  the  negatives  made  from  them. 

LITHOGRAPHY. 

ORIGINAL  PROCESS. 

The  general  term  "  lithography "  is  sometimes  used  to  indicate 
not  only  the  original  process  so  named,  said  to  have  been  invented 
by  Senefelder,  but  chromolithography,  photolithography,  and  en- 
graving on  stone,  as  well  as  engraving  on  copper  as  a  means  of  sup- 
plying matter  to  be  transferred,  to  and  printed  from  a  lithographic 
stone. 

Senefelder  discovered  that  limestone  will  absorb  either  grease  or 
water,  and  that  neither  one  will  penetrate  a  part  of  the  surface  pre- 
viously affected  by  the  other.  He  found  that  if  a  design  is  drawn 
on  limestone  with  a  greasy  crayon  and  the  stone  afterward  properly 
prepared  with  a  solution  of  nitric  acid  and  gum,  greasy  ink  will 


84  PREPARATION   OF  ILLUSTRATIONS. 

adhere  only  to  the  parts  that  are  covered  with  the  crayon,  and  that 
the  stone  will  give  off  an  iinpre^ion  of  the  design. 

Lithographic  stone  is  described  as  a  fine,  compact,  homogeneous 
limestone,  which  may  be  either  a  pure  carbonate  of  lime  or  dolomitic — 
that  is,  it  may  contain  magnesium.  Although  limestone  is  one  of 
the  most  common  rocks,  limestone  of  a  quality  suitable  for  use  in 
lithografthy  is  found  at  only  a  few  localities.^^  There  are  two  general 
classes  of  lithographic  stone,  known  to  the  trade  as  "  blue  "  or  hard 
stone  and  "yellow"  or  soft  stone.  The  blue  stone  is  adapted  for 
engraving  and  to  the  better  grade  of  fine-line  printing;  the  yellow 
stone  is  rated  as  somewhat  inferior. 

In  the  original  process,  which  may  here  be  termed  plain  lithog- 
raphy, two  methods  are  employed  in  putting  on  stone  the  design  to 
be  reproduced.  In  one  the  subject  or  picture  to  be  reproduced  is 
drawn  on  the  printing  stone  either  with  a  lithograi^hic  crayon  or 
with  a  pen  dipped  in  lithographic  ink  or  "tusche,"  which  is  oily 
or  fatty,  like  the  crayon.  In  the  other  method  the  drawing  is  made 
on  transfer  paper  and  transferred  to  the  stone.  In  drawing  on 
stone  it  is  necessary  to  reverse  the  design,  so  that  all  lettering  must 
be  drawn  backward.  In  doing  this  the  artist  often  uses  a  mirror 
to  aid  him.  If  the  drawing  is  made  on  transfer  paper  the  design 
and  the  lettering  are  copied  as  in  the  original — not  reversed. 

Before  a  drawing  is  made  on  stone  a  stone  of  the  quality  suited 
to  the  particular  design  in  hand  is  selected.  The  stone  is  then 
ground  and  polished,  and  if  the  drawing  is  to  be  made  with  crayon 
it  is  "grained"  according  to  the  special  requirements  of  the  subject. 
If  the  drawing  is  to  be  made  with  a  pen  and  is  to  consist  of  "  line 
work  "  the  stone  is  polished.  The  first  step  is  to  obtain  on  the  stone 
an  outline  or  "  faint "  of  the  design.  There  are  several  ways  to  do 
this.  By  one  method  a  tracing  of  the  design  is  made,  a  sheet  of 
thin  paper  covered  with  red  chalk  is  laid  face  downward  on  the 
stone,  the  tracing  is  laid  face  downward  over  it,  and  the  design  is 
again  traced  in  red-chalk  lines  on  the  stone.  The  method  described 
is  simple,  but  there  are  others  that  are  more  complicated  and  that 
are  particularly  applicable  to  the  reproduction  of  photographs  and 
other  illustrations.  Crayon  work  is  often  used  in  combination  with 
pen  and  ink,  stipple,  and  brush  work.  This  method  of  drawing  on 
stone  is  used  also  for  preparing  color  stones  in  the  process  of  chromo- 
lithography,  in  which  there  are  many  added  details  of  manipulation. 
After  the  drawing  has  been  made  on  the  stone  or  transferred  to  it 
the  stone  is  "gummed" — ^that  is,  it  is  covered  with  a  solution  of 
gum  arable  and  nitric  acid — and  dried.  The  stone  is  then  dampened 
with  water  and  carefully  rolled  with  lithographic  ink,  which  ad- 

"  Kubel,  S.  J.,  Lithographic  stone :  U.  S.  Geol.   Survey  Mineral  Resources,   1900,  pp. 
869-873,  1901. 


PREPAKATION  OF  ILLUSTRATION'S.  85 

heres  to  the  pen  or  crayon  work  and  is  repelled  elsewhere.  It  is 
then  "  rubbed  "  over  with  powdered  rosin  and  talcum,  which  adheres 
to  the  ink  and  further  protects  the  drawing  from  the  effects  of 
the  etching  fluid,  which  is  next  to  be  applied  to  the  stone.  This  fluid 
consists  of  a  10  per  cent  solution  of  gum  arabic  to  which  2  to  7  per 
cent  of  nitric  acid  has  been  added,  the  degree  of  acidity  being 
varied  according  to  the  subject  and  the  hardness  of  the  stone.  The 
fluid  is  applied  with  a  brush  or  sponge  and  is  left  on  the  stone 
just  long  enough  to  decompose  slightly  the  carbonate  of  lime  on  its 
surface  and,  after  washing,  to  leave  the  design  or  drawing  in  very 
slight  relief.  The  stone  is  again  gummed  and  dried,  and  the  design 
is  "  washed  out "  or  brought  out  by  removing  the  surface  gum  with 
a  wet  sponge  and  applying  to  the  stone  a  rag  sprinkled  with  turpen- 
tine and  charged  with  printing  ink.  These  operations  wash  away  the 
tusche  and  the  crayon  that  have  been  decomposed  by  the  acid  and 
expose  the  design  faintly  in  white  at  first,  but  it  gradually  gi'ows 
darker  as  it  becomes  charged  with  printing  ink  from  the  rag.  The 
stone  is  next  "  rolled  up  "  or  inked.  The  slightly  moistened  surface 
repels  the  ink  and  the  design  takes  it  up,  so  that  wdien  the  stone  is 
run  through  the  press  the  design  is  carried  to  the  paper. 

Lithographic  prints  from  stones  prepared  in  this  way  are  made 
on  a  flat-bed  press.  The  stone  is  carried  forward  to  print  and  on  its 
return  is  dampened  and  inked,  an  operation  slower  than  that  of  ro- 
tary printing. 

Corrections  and  changes  are  made  on  the  stone  by  carefully  scrap- 
ing or  polishing  away  the  parts  to  be  corrected  and  making  the 
changes  with  a  crayon  or  pen,  but  the  design  can  not  ordinarily  be 
corrected  twice  in  the  same  place,  as  the  scraping  or  polishing  re- 
moves a  part  of  the  surface  of  the  stone  and  thus  lessens  the  pressure 
at  that  place,  and  the  impression  there  may  be  imperfect  or  may 
completely  fail. 

This  form  of  lithography  is  seldom  used  for  Survey  illustrations 
but  was  formerly  much  used  and  is  well  adapted  to  the  reproduction 
of  drawings  of  fossils,  particularly  of  remains  of  dinosaurs  and  other 
types  of  large  extinct  animals.  Examples  may  be  seen  in  Monographs 
8  and  10  and  in  other  early  reports  of  the  Geological  Survey.  The 
drawings  for  these  illustrations  were  made  directly  on  stone. 

A  drawing  made  on  one  stone  may  be  transferred  in  duplicate  or 
in  any  desired  number  to  another  stone,  or  to  a  properly  grained 
sheet  of  zinc  and  aluminum,  from  which  impressions  may  be  printed 
on  a  lithographic  press.  Both  these  metals  are  also  used  for  litho- 
graphic printing  on  rotary  presses,  the  zinc  or  aluminum  plate  being 
bent  and  secured  around  a  cylinder  which  rotates  continuously  in 
one  direction.    As  one  impression  is  made  at  each  revolution  of  the 


86  PREPAEATION  OF  ILLUSTRATIONS. 

cylinder  the  printing  is  rapid;  but  the  best  printing  from  a  metal 
plate  is  inferior  to  the  best  printing  from  a  lithographic  stone. 

PHOTOLITHOGRAPHY. 

Photolithography,  like  other  lithographic  processes,  has  been  im- 
proved greatly  during  the  last  few  years — ^not  particularly  in  results 
but  in  methods — by  the  introduction  of  metal  plates,  the  rubber 
blanket  offset,  the  Ben  Day  films,  and  many  mechanical  and  chemical 
devices,  so  that  a  brief  description  of  it  will  not  explain  the  process 
except  in  a  most  general  way.  As  photolithography  is  a  direct  proc- 
ess and  is  relatively  cheap  it  is  the  one  most  used  for  reproducing 
large  maps  and  other  line  drawings  that  have  been  carefully  pre- 
pared. Zinc  and  aluminum  plates  are  now  much  used  in  photo- 
lithograpliy,  for  a  direct  contact  photographic  print  can  be  made  on 
them,  they  can  be  printed  flat  or  bent  for  use  on  a  rotary  press,  and 
they  can  be  stored  for  future  use  more  economically  than  stones. 

There  are  two  somewhat  distinct  methods  of  producing  photo- 
lithographs.  In  both  the  ordinary  photographic  methods  are  used, 
but  it  is  often  necessary  to  "  cut "  or  trace  parts  of  the  negative  in 
order  to  open  up  lines  and  other  features  that  are  not  sharp  or  well 
defined,  so  that  the  negative  will  print  them  sharp  and  clear.  If  the 
copy  to  be  reproduced  shows  three  colors,  three  negatives  are  made, 
one  for  each  color,  and  the  parts  to  be  shown  by  each  are  preserved 
by  "  opaquing  "  or  painting  out  all  other  parts.  By  the  older  method 
the  negative  thus  perfected  is  placed  in  a  printing  frame  in  contact, 
under  pressure,  with  sensitized  transfer  paper  and  is  exposed  to 
light.  The  printing  frame  is  then  carried  to  the  dark  room  and  the 
paper  is  removed  from  the  frame  and  its  surface  covered  with  trans- 
fer ink.  The  paper  is  then  laid  face  upward  on  water  and  soaked 
for  several  minutes,  after  which  it  is  placed  in  the  same  position  upon 
a  slab  of  stone  or  metal  and  thorougldy  washed  with  water.  This 
washing  removes  the  ink  and  the  sensitive  film  from  the  parts  that 
were  unaffected  by  the  action  of  light  (the  parts  corresponding  to  the 
white  paper  in  the  design),  but  the  ink  still  adheres  to  the  lines  of 
the  design  in  the  precise  sharpness  and  clearness  of  the  negative. 
The  design  is  now  ready  to  be  transferred  to  the  printing  stone  or 
zinc  plate.  The  sheet  is  again  slightly  dampened  between  moist 
blotters  and  laid  face  downward  in  its  correct  position  on  a  prepared 
stone  or  zinc  plate,  which  is  then  pulled  through  a  press  under  heavy 
pressure.  The  paper  is  then  removed  from  the  stone  or  plate,  to 
which  it  has  carried  the  design.  From  this  point  the  gumming, 
etching,  and  other  operations  are  practically  the  same  as  those  used 
in  ordinary  lithography. 


PREPAEATION  OF  ILLUSTRATIONS.  87 

The  bichromate-gelatin  transfer  process  described  above  has  been 
replaced  in  the  Survey  by  a  more  satisfactory  one,  which  insures 
absolute  scale  and  reproduces  the  finest  line  drawings  perfectly  with- 
out thickening  the  lines  or  without  distortion.  In  this  process,  which 
is  known  as  the  planographic  process,  a  photographic  negative  of  the 
"  copy  "  is  placed  in  a  vacuum  printing  frame  in  contact  with  a  zinc 
or  aluminum  plate  that  has  been  sensitized  with  a  bichromate-albumen 
solution  and  exposed  in  front  of  an  arc  lamp.  After  proper  exposure 
the  plate  is  removed  from  the  frame,  inked  over,  and  placed  under 
water.  The  parts  not  hardened  by  the  action  of  light  (the  unexposed 
parts)  are  then  rubbed  away  with  cotton,  and  the  plate  is  chemically 
etched,  gummed  over,  and  dried.  The  plate  is  then  ready  to  be 
printed  from  in  a  lithographic  press.  If  a  large  map  is  to  be  repro- 
duced it  is  photographed  in  parts,  and  contact  prints  are  made  on 
zinc  plates.  From  these  plates  transfers  are  pulled  and  the  parts  are 
assembled  and  laid  down  in  proper  position  on  a  stone  or  an  aluminum 
plate,  which  is  then  prepared  for  printing. 

A  drawing  that  is  to  be  reproduced  by  photolithogi-aphy  should  be 
made  on  pure-white  paper  in  lines,  dots,  or  black  masses  with  black 
waterproof  ink.  It  should  be  one  and  one-half  to  two  or  three  times 
the  size  of  the  finished  print. 

Photolithography  is  particularly  adapted  to  the  reproduction  of 
maps,  plans,  and  other  large  drawings.  Within  certain  limitations, 
lines  may  be  changed  and  details  may  be  added  after  proofs  have 
been  submitted.  The  process  is  ordinarily  used  for  reproducing 
illustrations  in  one  color  (black) ,  but  it  is  used  also  for  printing  in 
more  than  one  color,  generally  over  a  black  outline  base,  each  color 
being  printed  from  a  separate  stone,  as  in  chromolithography. 

OFFSET  PRINTING. 

In  the  offset  process  the  design  is  "  offset "  from  a  lithographic 
plate  or  stone  to  a  rubber  blanket  on  a  ejdinder,  from  which  it  is 
printed.  By  thus  obtaining  an  impression  from  an  elastic  surface 
the  finest  details  can  be  printed  on  rough,  uncoated  paper,  which  can 
not  be  used  in  other  processes,  which  can  be  folded  without  danger 
of  breaking,  and  which  is  more  durable  than  coated  paper.  Plates 
II,  III,  IV,  VII,  and  Ylll  in  this  pamphlet  were  printed  by  this 
process. 

CHROMOLITHOGRAPHY. 

The  chromolithographic  process,  by  which  illustrations  are  printed 
in  color  from  stone,  is  used  in  Survey  publications  principally  for  re- 
producing geologic  maps,  but  it  is  sometimes  used  for  reproducing 
colored  drawings  of  specimens. 

861754° — 49 7 


88  PREPARATION  OF  ILLUSTRATIONS. 

There  are  several  kinds  of  color  printing  from  stones.  One  pro- 
duces a  picture  by  superimposing  colors  that  combine  and  overlap 
without  definite  outlines  and  thus  reproduce  the  softly  blended  colors 
of  the  original.  Another  reproduces  the  original  by  printing  colors 
within  definite  outlines  on  a  "  base "  which  has  been  previously 
printed  in  black.  The  first  kind  is  used  by  the  Survey  for  repro- 
ducing colored  drawings  of  specimens.  The  second  is  followed  in 
reproducing  geologic  maps. 

As  each  color  must  be  printed  from  a  separate  stone  and  properly 
fitted  with  respect  to  the  others  a  tracing  from  the  original  is  made 
of  the  precise  outlines  of  each  color;  or,  if  the  design  is  to  be  re- 
duced, a  tracing  is  made  over  a  properly  reduced  photographic  print. 
This  tracing  can  be  made  on  specially  prepared  tracing  paper  or  on  a 
sheet  of  transparent  gelatin  or  celluloid,  which  is  laid  over  the  copy 
and  on  which  all  the  outlines  and  overlaps  of  the  various  colors  are 
scratched  with  a  steel  point.  The  scratches  thus  made  on  the  celluloid 
are  filled  with  red  chalk  or  like  substance,  and  rubbed  in  with  cotton, 
and  by  reversing  the  sheet  and  rubbing  it  the  chalk  lines  are  deposited 
on  as  many  stones  as  are  needed  to  produce  the  colors  of  the  original 
design,  each  stone  bearing  all  the  outlines  of  the  design.  Sometimes 
all  the  outlines  are  engraved  on  what  is  called  a  key  stone  and  an 
impression  from  it  is  laid  down  on  each  of  the  color  stones.  The 
parts  on  each  stone  that  are  to  have  one  color  are  then  inked  in  or 
engraved,  and  at  the  same  time  guide  marks  are  indicated,  so  that  in 
the  composite  print  from  the  stones  each  color  will  fit  its  proper  place. 
This  fitting  is  called  "  register  "  and  is  an  important  part  of  printing, 
for  each  stone  must  be  adjusted  to  a  nicety  while  on  the  press  in  order 
to  make  each  impression  fit  the  others  exactly.  The  process  was  orig- 
inally manipulated  entirely  by  hand,  but  photography  has  now  re- 
placed much  of  the  handwork  and  has  given  Tise  to  several  methods 
by  which  the  same  kinds  of  subjects  are  reproduced  in  radically 
different  ways.  Tints  are  sometimes  produced  by  the  half-tone  and 
other  screens  and  by  machine  ruling,  and  printer's  type  is  used  almost 
exclusively  for  titles  and  other  matter  that  was  formerly  engraved  or 
drawn  on  the  stone. 

In  reproducing  a  geologic  map  the  base  may  be  engraved  on  stone 
or  on  copper  or  it  may  be  photolithographed.  By  either  process  the 
map  may  be  transferred  to  the  printing  stone.  The  color  stones  for 
geologic  maps  are  prepared  by  hand,  but  the  geologic  patterns,  which 
are  printed  in  colors,  are  engraved  separately  on  plates,  from  which 
impressions  are  pulled  when  needed  and  transferred  to  their  proper 
places  on  the  printing  stones  in  the  shapes  required  according  to  the 
"  key  "  design.  The  lighter,  more  transparent  colors  are  generally 
printed  first,  and  often  twelve  or  more  colors  and  many  dis- 
tinctive patterns  are  used  to  produce  a  geologic  map.    When  proofs 


PKEPARATION  OF  ILLUSTRATIONS.  89 

of  such  a  map  are  pulled  each  stone  must  be  taken  up  and  carefully 
adjusted  on  the  press,  so  that  the  work  of  proving  maps  that  are 
printed  from  a  considerable  number  of  color  stones  is  laborious  and 
expensive.  It  is  therefore  customary  to  approve  first  combined  proofs 
conditionally — that  is,  subject  to  the  corrections  and  changes  indi- 
cated on  the  proofs — and  to  hold  the  lithographer  responsible  for  any 
failure  to  make  the  corrections. 

This  process  is  the  most  expensive  one  used  for  reproducing  illus- 
trations. Changes  may  be  indicated  on  proofs,  but  changes  can  not 
be  made  on  a  stone  twice  in  the  same  place  without  danger  of  affect- 
ing the  printing  or  making  it  necessary  to  retransfer  the  parts  af- 
fected. All  changes  are  expensive  because  a  slight  modification 
at  one  point  may  involve  corresponding  changes  on  a  number  of 
stones,  each  of  which  must  be  taken  up,  corrected,  and  proved  to  in- 
sure the  exact  coincidence  of  the  parts  affected.  It  is  often  less  ex- 
pensive to  retransfer  the  entire  job  than  to  make  extensive  changes 
on  the  original  stones. 

ENGRAVING  ON  STONE  AND  ON  COPPER. 

Engraving  on  stone  is  distinctly  lithographic,  but  engraving  on 
copper  is  sometimes  included  among  lithographic  processes  because 
the  work  produced  by  it  is  usually  printed  from  stone  and  thus  be- 
comes lithographic.  In  other  respects  engraving  on  copper  is  not  a 
lithographic  process.  Roughly  prepared  maps  and  any  rough  line 
copy  that  is  accurate  in  statement  and  clear  as  to  intent  are  appro- 
priate for  both  methods  of  engraving,  but  drawings  that  are  expertly 
prepared  are  more  suitable  for  reproduction  by  photolithography. 
In  engraving  on  stone  the  lines  of  a  design  are  scratched  on  the 
blackened  surface  of  a  stone  with  a  steel-pointed  tool ;  in  engraving  on 
copper  the  lines  are  cut  with  a  graver  on  a  sheet  or  plate  of  copper, 
the  matter  to  be  engraved  being  first  shown  on  the  plate  by  what  is 
called  the  photo-tracing  process,  which  was  devised  in  the  Geological 
Survey.  There  is,  however,  no  great  or  essential  difference  in  the 
printed  results  of  the  two  processes,  but  most  lithographers  employ 
only  stone  engravers. 

A  stone  on  which  a  design  is  to  be  engraved  is  ground  and  pol* 
ished  according  to  the  kind  of  work  to  be  engraved,  is  coated  with  a 
thin  solution  of  gum  arable  and  allowed  to  dry,  and  is  then  washed 
until  the  superficial  gum  is  removed  while  the  surface  pores  remain 
filled.  As  the  lines  made  by  the  engraver  must  be  visible  the  stone  is 
blackened  with  a  pigment  composed  of  lampblack  and  gum  or  is 
covered  evenly  with  red  chalk  or  Venetian  red.  It  is  then  ready  to 
receive  the  design  to  be  engraved. 

If  the  design  is  a  map  which  is  to  show  culture,  streams,  and  sur- 
face contours,  and  each  of  these  sets  of  features  is  to  be  printed  in  a 


90  PREPARATION  OF  ILLUSTRATIONS. 

i^parate  color,  impressions  of  the  work  to  be  engraved  must  be  placed 
on  three  stones.  One  method  of  doing  this  is  to  make  a  scratch 
tracing  of  the  original  drawing  on  a  sheet  of  transparent  gelatin 
or  celluloid  in  the  manner  employed  in  chromolithography,  except 
that  a  dry  pigment,  generally  chrome-yellow,  is  used  to  fill  the 
scratch  lines  instead  of  red  chalk  or  Venetian  red.  From  this 
tracing  a  "  faint "  or  imprint  of  all  the  details  of  the  three  separate 
features  of  the  map  is  made  on  each  of  the  three  stones,  and  the  en- 
graver then  cuts  on  each  stone  only  the  lines  and  other  features,  in- 
cluding ample  register  marks,  that  are  to  be  printed  in  one  color,  the 
imprint  made  from  the  tracing  making  it  possible  to  engrave  each  set 
of  features  in  its  exact  position  relative  to  the  other  two.  By  an- 
other method  the  matter  to  be  engraved  is  photographed  directly  on 
the  stone. 

The  engraving  is  done  with  a  steel  needle  inserted  in  a  small 
wooden  cylinder,  an  instrument  resembling  an  ordinary  lead  pencil. 
The  size  and  shape  of  the  needles  used  are  varied  according  to  the  re- 
quirements of  the  matter  to  he  engraved.  With  this  instrument  the 
lines  and  lettering  are  lightly  scratched  into  the  stone  through  the 
dark  coating  and  show  as  light  lines.  The  points  of  some  of  the 
needles  are  fine ;  those  of  others  are  V-shaped ;  and  some  have  spoon- 
shaped  points,  for  use  in  thickening  lines  and  shading  letters.  All 
features  are  engraved  in  reverse. 

After  the  engraving  is  completed  the  stones  are  prepared  for  print- 
ing by  wiping  off  all  the  superficial  color  and  filling  the  engi'aved 
lines  with  a  greasy  ink — generally  a  thin  printing  ink — which  is 
rubbed  into  the  lines  with  a  soft  rag.  Impressions  are  then  pulled 
on  transfer  paper  and  transferred  to  three  printing  stones  for  use  in 
printing  the  three  colors,  the  register  marks  enabling  the  pressman 
to  fit  each  color  exactly  in  its  proper  place. 

In  all  lithogi'aphic  processes  the  titles  and  other  marginal  lettering 
can  be  and  usually  are  transferred  from  type  impressions  to  the 
printing  stones.  It  is  therefore  unnecessary  to  letter  such  matter 
carefully  on  an  original  drawing  that  is  made  for  lithographic  repro- 
duction, for  appropriate  faces  of  type  will  give  better  printed  results 
than  hand  lettering. 

Corrections  can  not  be  made  on  a  stone  or  copper  engraving  as 
readily  as  on  a  drawing.  If  a  stone  engraver  makes  an  error  or  if  a 
change  is  required  after  his  engi-aving  is  finished,  the  parts  to  be 
corrected  must  be  scraped  off  and  a  new  ground  laid  before  the  correc- 
tion can  be  made.  Sometimes  he  will  engrave  the  parts  corrected  on 
another  part  of  the  original  stone  and  transfer  it  to  the  printing 
stone.  Corrections  are  made  on  copper  plates  by  "  hammering  up  " 
the  plate  from  beneath,  polishing  off  a  new  surface,  and  reengraving 
the  part  to  be  corrected. 


APPENDIX. 

The  matter  given  in  this  appendix  is  much  used  in  making  geologic 
maps  and  other  illustrations.  The  Greek  alphabet  and  the  groups  of 
signs  presented  are  given  chiefly  to  show  the  correct  formation  of  each 
letter  and  sign. 

MISCELLANEOUS  TABLES. 

Length  of  1°  of  longitude  measured  along  given  parallels  from  the  Equator  to 

the  poles. 

[From  U.  S.  Coast  and  Geodetic  Survey  Report  for  1884,  Appendix  6.] 


Parallel  of  latitude. 

Statute 
miles. 

Parallel  of  latitude. 

Statute 
miles. 

Parallel  of  latitude. 

Statute 
miles. 

0 

69. 172 
69. 162 

69. 130 
69. 078 
69. 005 
68.911 
68. 795 
68.660 
68.504 
68. 326 
68.129 
67.910 
67.670 
67.410 

67. 131 
66.830 
66. 510 
66. 169 
65.808 
65.  427 
65. 026 
64.606 
64. 166 
63. 70*', 
63. 228 
62.  729 
62.212 
61. 676 
61. 122 
60. 548 
59. 956 

31...     . 

59.365 
58.716 
58. 071 
57.407 
56.725 
56.027 
65.311 
54. 579 
53.  829 
53. 063 
52.  281 
51.483 
50. 669 
49.840 
48.995 
48. 136 
47. 261 
46. 372 
45. 469 
44. 552 
43.621 
42. 676 
41.719 
40. 749 
39.766 
38. 771 
37.764 
36. 745 
35. 716 
34.674 

61 

33  623 

1 

32 

62 

32  560 

2 

33 

63 

31  488 

3 

34 

64 

30  406 

4 

35 

65. 

29  315 

5 

36 

66 

28  215 

6 

37 

67     . 

27  106 

7 

38 

68 

25  988 

8 

39 

69 

24  862 

9 

40 

70 

23  729 

10 

41 

71 

22  589 

11 

42 

72 

21  441 

12 

43 

73 

20  287 

13 

44 

74 

19  127 

14 

45 

75 

17  960 

15 

46 

76 

16.788 

16 

47 

77  .     ... 

15  611 

17 

48 

78 

14.428 

18 

49 

79 

13.242 

19 

50 

80 

12  051 

20 

51 

81 

10.857 

21.           

52 

82 

9.659 

22 

53 

83 

8.458 

23                        .         .   .   . 

54 

84 

7.255 

24 

55 

85 

6.049 

25 

56 

86 

4.842 

26 

57 

87 

3.632 

27 

58 

88 

2.422 

28         

59 

89 

1.211 

29 

60 

90 

.000 

30 

Length  of  1°  of  l<ititiide  measured  along  a  meridian  at  gif>en  parallels. 
[Parallel  given  is  in  center  of  the  degree  whose  length  is  stated.] 


Parallel  of  latitude. 

Statute 
miles. 

Parallel  of  latitude. 

Statute 
miles. 

0 

68. 704 
68.725 
68.  786 
68. 879 
68.993 

50 

69.115 
69.  230 
69. 324 
69.  386 
69. 407 

10 

60 

20 

70 

30 

80 

40 

90 

91 


92 


PREPAEATION  OF  ILLUSTRATIONS. 


Metric  system  and  equivalents. 

[The  units  of  linear  measure  most  commonly  used  are  millimeters  (mm.),  centimeters  (cm.),  decimeters 
(dm.),  meters  (m.),  and  kilometers  (km.).  1  m.=  10  dm.;  1  dm. =  10  cm.;  1  cm. =  10  mm.;  1  km. =  1,000 
meters=  0.62137  mile;  1  m.=39.37  inches=  3.280833  feet.] 


Meters. 

Inches. 

Meters. 

Feet. 

Kilometers. 

Miles. 

1 

39.37 
78.74 
118.11 
1.57.48 
196.85 
236.22 
275. 59 
314.% 
354.33 

I 

3. 280833 
6.561667 
9.842500 
13. 123333 
16.404166 
19.685000 
22. 965833 
26. 246666 
29.527500 

1 

0. 62137 

2 

2 

2 

1  24274 

3 

3 

3 

1.86411 

4 

4 

4 

2. 4K548 

5 

5 

5 

3. 10685 

6 

6 

6     .. 

3.72822 

7 

7 

7 

4. 34959 

8 

8 

8 

4.97096 

9 

9::::::::::.::::::::::: 

9 

5.59233 

Inches. 

Centi- 
meters. 

Feet. 

Meters. 

MUes. 

Kilo- 
meters. 

1 

".54 
5.08 
7.62 
10.16 
12.70 
15.24 
17.78 
20.32 
22.86 

1 

0. 304801 
0.609601 
0.914402 
1.219202 
1.524003 
1.828804 
2. 133604 
2. 438405 
2.743205 

1 

1.60935 

2 

2 

2 

3.21869 

3 

3 

3 

4. 82804 

4 

4 

4 

6.  -13739 

5 

5 

5 

8.04674 

6 

6 

6 

9. 65608 

7 

7 

7 

11.26543 

8 

8 

8              

12. 87478 

9 

9 

9 

14. 48412 

The  "  vara,"  used  in  Texas,  is  equivalent  to  33J  inches  and  is  computed  as  representing 
2.78  feet. 

Geologic  eras,  periods,  systems,  epochs,  and  series. 


Era. 

Period  or 

system. 

Ejwch  or  series. 

Quaternary 

/Recent. 

\Pleistocene  (replaces  "Glacial"). 

[Pliocene. 

J  Miocene. 

C«n0M)ic 

Mesozolc 

Cretaceous 

Jurassic 

1  Oligocenc. 

1  Eocene. 

/Upper  (Gulf  may  be  used  provincially). 

\Lower  (Comanche  and  Shasta  may  be  used  provincially). 

(Upper. 

]  Middle. 

[Lower. 

Upper. 

Middle. 

Carbonifero 

Devonian.. 

Silurian. 

Ordovician 

Cambrian . . 

Algonkian. 
.Archean. .. 

us 

Lower. 
1  Permian. 

•{Pennsylvanian  (replaces  "Upper  Carboniferous"). 
IMississippian  (replaces  "Lower  Carboniferous''). 

Upper. 
■{Middle. 

Paleozoic 

[Lower. 

(Upper  (Cincinnatian  may  be  used  provincially). 
^Miadle  (Mohawkian  may  be  used  provincially). 
(Lower. 
Saratogan  (or  Upper  Cambrian). 

Protcrozoic 

Ipre-Cam- 
/    brian. 

[Waucoban  (or  Lower  Cambrian). 

PEEPARATION   OF  ILLUSTRATIONS. 
Chemical  elements  and  sym'bols. 


93 


Element. 

Symbol. 

Element. 

Symbol. 

Element. 

Symbol. 

Aluminum 

Al 

Sb 

A 
As 
Ba 
Bi 

B 

Br 

Cd 

Cs 

Ca 

C 

Ce 

CI 

Cr 

Co 

Cb 

Cu 

gy 

Er 

Eu 

F 

Gd 

Ga 

Ge 

Gl 

Au 

He 

Holmium      

Ho 
H 
In 
I 

Ir 

Fe 

Kr 

La 

Pb 

Li 

Lu 

Mg 

Mn 

Hg 

Mo 

Nd 

Ne 

Ni 

Nt 

N 

Os 

0 

Pd 

P 

Ft 

K 

Pr 

Ra 

Rhodium 

Rh 

Antimony 

Rubidium 

Rb 

Argon...". 

Ruthenium 

Ru 

Arsenic. 

Iodine 

Samarium 

Sa 

Barium 

fVnnrliiim . 

Sc 

Selenium 

Se 

Boron 

Krypton 

Silicon 

Si 

Bromine                       .  . 

T.finthaniiTn.    . 

Silver 

Aft 

Lead 

Sodium 

N8 

Caesium             

Lithium 

Strontium 

Sr 

Luteciiun 

Sulphur 

S 

Carbon 

Magnesium 

Tantalum. 

Ta 

To 

Chlorine 

Mercury 

Terbium     

Tb 

Chromiimi 

Molybdenum 

Thallium 

Tl 

Cobalt 

Th 

Columbium 

Neon 

Thulium 

Tm 

Copper 

Nickel 

Tin 

Sn 

Dysprosium 

Niton 

Ti 

Erbium 

Nitrogen. 

Tungsten 

W 

Europium 

Osmium 

Uraniiun 

U 

Fluorine. 

Oxygen 

V 

Xe 

Galliiun. 

Ytterbiimi  (Neoytter- 
bium) 

Germaniuni 

Platinum 

Yb 

Glueinum 

Yttrium 

Y 

Gold 

Praseodymium 

Zinc 

Zn 

HelJiiT"  . 

Zr 

Greek  alphabet. 


Caps. 

Lower- 
case. 

Greek  name. 

English 
soimd. 

Caps. 

Lower- 
case. 

Greek  name. 

English 
sound. 

A 

a 

Alpha. 

A. 

N 

V 

Nu. 

N. 

B 

^6 

Beta. 

B. 

2 

? 

Xi. 

X. 

r 

7 

Gamma. 

G. 

0 

0 

Omicron. 

0  short. 

A 

6 

Delta. 

D. 

n 

TT  tS 

Pi. 

P. 

E 

e 

Epsilon. 

E  short. 

p 

P 

Rho. 

R. 

Z 

f 

Zeta. 

Z. 

2 

s  cr 

Sigma. 

S. 

H 

n 

Eta. 

E  long. 

T 

T 

Tau. 

T. 

G 

0t? 

Theta. 

Th. 

T 

V 

Upsilon. 

U. 

I 

I 

Iota. 

I. 

* 

4><p 

Phi. 

F. 

K 

K 

Kappa. 

K. 

X 

X 

Chi. 

Ch. 

A 

X 

Lambda. 

L. 

^ 

\p  a 

Psi. 

Ps. 

M 

M 

Mu. 

M. 

fi 

w 

Omega. 

0  long. 

Roman  numerals. 


1 1 

il... 2 

m 3 

r\' i 

V 5 

Vt 6 

vn 7 

vm 8 


IX 9 

X 10 

XIX 19 

XX 20 

XXX 30 

XI 40 

L 50 

LX 60 


LXX 70 

LXXX 80 

XC 90 

C 100 

GL 150 

CO 200 

CCC 300 

CD 400 


D 500 

DC 600 

DCC 700 

DCCC 800 

CM 900 

M 1000 

MD 1500 

MCM..    1900 


H 


PREPARATION  OF  ILLUSTRATIONS. 


Mathematical  signs. 


+  plus. 

—  minxis. 

X  multiplied  by. 

■T-  divided  by. 

•=  equality. 

±  plus  or  minus. 

D  square. 

O  rectangle. 


A  triangle. 

0  circle. 
^  angle. 

L  right  angle. 
C  or  >  greater  than. 
"D  or  <  less  than. 

1  perpendicular. 
~  difference 


y   integration. 
O  equivalence. 
:  ratio. 

■H-  geometrical  propor- 
tion. 
— ;  difference,  excess. 
.•.  therefore. 


■.■  because. 
CO  infinity, 
y  varies  as. 
v'  radical. 


minute. 
■  second. 


NAMES  OF  ROCKS. 

The  following  list  was  prepared  in  the  geologic  branch  for  the  use 
of  geologic  draftsmen  to  enable  them  to  select  appropriate  symbols 
for  rocks  that  may  be  referred  to  in  preliminary  drawings  by  name 
only.  For  sedimentary  rocks  dots  and  circles,  parallel  lines,  and 
broken  or  dotted  lines  are  used ;  for  metamorphic  rocks  short  dashes 
arranged  without  definite  patterns;  and  for  igneous  Tocks  patterns 
composed  of  short  dashes,  triangles,  rhombs,  crosses,  and  cross  lines. 
All  these  patterns  are  shown  in  Plate  III. 

Sedimentary  material. 

[Including  residual,  detrital,  eolian,  glacial,  organic,  and  chemically  precipi- 
tated material.] 


Agglomerate. 

Alabaster. 

Alluvium. 

AJum  shale. 

Anhydrite. 

Apron  (alluvial). 

Argillite. 

Arkose. 

Asphalt. 

Bench  gravel. 

Bentonite. 

Boulder  clay. 

Brea. 

Breccia. 

Brownstone. 

Burrstone. 

Calcarenite, 

Calc  sinter. 

Caliche. 

Catlinite. 

Chalk. 

Chert. 

Clay. 

Coal. 

Conglomerate. 

Coprolite. 

Coquina. 


Detritus. 

Diatomaceous  earth. 

Diluvium. 

Dolomite. 

Drift. 

Fan    (alluvial). 

Fanglomerate. 

Flagstone. 

Flint. 

Freestone. 

Fuller's   earth. 

Geyserite. 

Gravel. 

Graywacke. 

Greensand. 

Grit. 

Gumbo. 

Gypsum. 

Hardpan. 

Hematite. 

Infusorial  earth. 

Ironstone  (also  igneous). 

Itacolumite. 

Kame. 

Kaolin. 

Laterite. 

Lignite. 


Limestone. 

Limonite. 

Loess. 

Marble  (also  metamor- 
pliic). 

Marl. 

Metaxite. 

Morainal   deposit. 

Mudstone. 

Novaculite. 

Peat. 

Pelite. 

Phosphate  rock. 

Phosphorite. 

Phthanite. 

Psammites. 

Psephites. 

Puddingstone. 

Pyroclastic   material. 

Quartzite  (also  metamor- 
phic). 

Reddle. 

Rock  salt. 

Rock  stream. 

Rubble. 

Salt. 

Sand. 


PREPARATION  OF  ILLUSTRATIONS. 


95 


Sedimentary  waferiat— Continued. 


Sandstone. 

Stalagmite. 

Tufa     (=chemically    de- 

Selenite. 

Talc. 

posited  lime). 

Shale. 

Talus. 

Tuff    (=  igneous    frag- 

•Silt. 

Till. 

ments). 

Slate  (alsometamorphic). 

Travertine. 

Wacke. 

Soil. 

Tripoli. 

Wash. 

Stalactite. 

Metamorphio  material. 

Adinole. 

Garnet  rock. 

Ophicalcite. 

Amphibolite. 

Garnet  schist. 

Ottrelite  schist. 

Andalusite  schist  (?). 

Gneiss. 

Phyllite. 

Apo  (rhyolite),  etc. 

Granite  gneiss. 

Porcelanite. 

Argillite. 

Graywacke  (?). 

Protogene. 

All  gen  gneiss  (also  igne- 

Green schists. 

Pyroschists. 

ous). 

Greenstone     (also 

Quartz. 

Biotite  schist. 

igneous) . 

Quartzite. 

•Calc  schist. 

Greisen. 

Quartz  schist. 

■Cataclastic. 

Halleflinta. 

Schist. 

Chlorite  schist. 

Hornblende  schist. 

Sericite  schist,  etc. 

Clay  slate. 

Homfels. 

Serpentine. 

Damourite  schist. 

Horustone. 

Slate. 

Desmosite. 

Itabirite. 

Soapstone. 

Dynamometamorphic 

Kinzigite. 

SodaUte. 

rock. 

Knotenschiefer. 

Spilosite. 

Eclogite. 

Knotty  schists. 

Steatite. 

Epidosite. 

Lusulianite  (igneous?). 

Talc  schist. 

Erlan. 

Marble. 

Topazfels. 

Erlanfels. 

Meta  (diabase),  etc. 

Topaz  rock. 

Eulysite. 

Mica  schist. 

Zobtenite. 

Fibrolite  schist. 

Mylonite. 

Igneous  material. 

Absarokite. 

Aplite. 

Carmeloite. 

Abyssal. 

Arkite. 

Cascadite. 

Adamellite. 

Atatschite. 

Chibinite. 

Adendiorite. 

Augen  gneiss  (also  meta- 

Ciminite. 

Ailsyte. 

morphic) . 

Comendite. 

Akerite. 

Angitite. 

Complementary  rocks. 

Alaskite. 

Avezacite. 

Coppaelite. 

Albitite. 

Banakite. 

Cortlaudite. 

Allivalite. 

Banatite. 

Cromaltite. 

Allochetite. 

Bandaite. 

Cumberlandite. 

Ahioite. 

Basalt 

Cuselite. 

Alsbachite. 

Basanite. 

Dacite. 

Ambonite. 

Beerbachite. 

Dellenite. 

Amherstite. 

Bekinkinite. 

Diabase. 

Analcitite. 

Bombs. 

Diallagite. 

Andesite. 

Borolanite. 

Dike  rock. 

Anorthosite. 

Bostonite. 

Diorite. 

Aphanitite. 

Camptonite. 

Ditroite. 

96 


PKEPAEATION   OF  ILLUSTRATIONS. 


Igneous  mafenoJ-MUontinued. 


Dolerite. 

Dnnite. 

Durbachite. 

Effusive  rock. 

Ekerite. 

Elvan. 

Enstatite. 

Eruptive  rock. 

Essexite. 

Estrellite. 

Eulysite. 

Extrusive  rock. 

Farrisite. 

Felsite. 

Felsophyre. 

Fergusite. 

Fortunite. 

Four  Chi  te. 

Foyaite. 

Gabbro. 

Gauteite. 

Garewaite. 

Giumarrlte. 

Gladkaite. 

Granite. 

Granitite. 

Granitoid. 

Granodiorite. 

Granophyre. 

Greenstone    (also    nieta- 

morpliic). 
Greisen? 
Grorudite. 
Harrisite. 
Harzburgite. 
Haiiynophyre. 
Hawaiite. 
Hedrumite. 
Heumite. 
Holyokeite. 
Hornblendite. 
Hypabyssal  rock. 
Hyperite. 
Hypersthenlte. 
Ijolite. 

Intrusive  rock. 
Irruptive      (=intrusive) 

rock. 
Isenite. 
Jacupiranglte. 
Jumillite. 
Kaiwekite. 


Kedabekite. 

Kentallenite. 

Kenyite. 

Keratophyre. 

Kersantite. 

Kimberlite. 

Kohalaite. 

Krablite. 

Krageroite. 

Kulaite. 

Kyschytymite. 

Lamprophyre. 

Latite. 

Laugenite. 

Laurdalite. 

Laurvikite. 

Lava. 

Lestiwarite. 

Leucite  basalt. 

Leucite  tephrite. 

Leucitite. 

Leucocratic. 

Lherzolite. 

Linibergite. 

Lindoite. 

Liparite. 

Litchfieldlte. 

Lithoidite. 

Luciites. 

Lujaurite. 

Madrupite. 

Maenaite. 

Magma  basalt. 

Malchite. 

Malignite. 

Mangerite. 

Mariupolite. 

Melaphyre. 

Melilite  basalt. 

Mesanite. 

Mica  peridotite. 

Miuette. 

Missourite. 

Monchiquite. 

Mondholdeite. 

Monmoutbite. 

Monzonite. 

Mugearite. 

Naujaite. 

Nelsonite. 

Nephelinite. 

Nevadite. 


Nordmarkita 

Norite. 

Obsidian. 

Odinite. 

Orbite. 

Orendite. 

Ornciite. 

Orthophyrfe 

Ortlerite, 

Ouachitite. 

Paisanite. 

Pantellerite. 

Pegmatita 

Peridotite. 

Perknite. 

Perlite. 

Phanerite. 

Phonolite. 

Pierite. 

Pitehstone. 

Plagiaplite. 

Plagioclastic. 

Plumasite. 

Plutonic  rock. 

Pollenite. 

Porphyry. 

Pulaskite. 

Pumice. 

Pyroxeuite. 

Rhombenporphyry. 

Rhyolite. 

Rizzonite. 

Rockalite. 

Santorinite. 

Sanukite. 

Saxonite. 

Scyelite. 

Shastaite. 

Shonkinite. 

Shoshonite. 

Soda  granite. 

Solvsbergite. 

Sommaite. 

Spessartita 

Sussexite. 

Syenite. 

Taimyrite. 

Tavpite. 

Tephrite. 

Teschenite. 

Therallte. 

Tilaite. 


PREPARATION  OF  ILLUSTEATIONS. 


97 


Igneous  material — Continued. 


Tinguaita 

Tjosite. 

Tonalite. 

Tonsbergite. 

Tordrillite. 

Toscanite  (?). 

Trachy-andesite. 

Trachyte. 

Trap. 


Troctolite. 

Umptekite. 

Unakite. 

Ungaite, 

Urtite. 

Valbellite. 

Venanzite. 

Verite. 

Vitrophyre; 


Yogesite. 

Volcanic  rock. 

Volhynite. 

Vulsinite. 

Websterite. 

Wehrlite. 

Windsorite. 

Wyomingite. 

Yamasklte. 


INDEX. 


A.  Page. 

Abbreviations,  forms  of 55-57 

Adhesive  materials,  choice  of 37 

Alaska,  maps  of,  reuse  of 17 

Albertype.    See  Photogelatin  processes. 

Apparatus,    photographs    of,    preferred    to 

sketches 29 

Approval  of  finished  drawings,  features  to  be 

covered  by 38 

of  illustrations,  regulations  governing 8-9 

Areas,  patterns  used  to  distinguish 23 

patterns  used  to  distinguish,  plate  show- 
ing         62 

Army,  Corps  of  Engineers  of  the,  maps  pub- 
lished by 15 

Artotype.    See  Photogelatin  processes. 

Atlases,  published,  use  of 15 

B. 
Base  maps.    See  Maps,  base. 
Bleaching  photographic  prints,  method  and 

solutions  for 69 

Border  for  maps,  width  and  use  of. 57-58 

Bristol  board,  kind  and  sizes  used 24, 66 

Brush  and  pencil  drawings,  materials  and 

methods  used  in  making 66-67, 69 

Brushes,  kinds  and  sizes  used 66-67,71 

C. 
Celluloid  transferring,  process  of 47 

requisitions  for 47 

Cerotype  process,  description  and  advantages 

of 80-81 

Changes  in  engravings,  possible  kinds  of. .  38-39,90 
Changes  in  original  material,  draftsman  to 

consult  author  on 65 

Chemical  elements,  names  and  symbols  of . . .       93 

Chromolithography,  description  of 87-89 

Civil  divisions,  lettering  of 53,54 

Coal  beds,  indication  of  thickness  of 31 

C'Oast  and  Geodetic  Survey  charts,  use  of 15 

Collotype.    See  Photogelatin  processes. 

Coloring  materials,  use  of 26 

Colors,  standard,  for  geologic  maps 62-63 

use  of,  for  ground-water  features 21-23 

on  original  geologic  maps 27-28 

Commas,  form  of 54 

use  of,  in  numbers 54 

Contours,  drawing  of 48-50 

Cooperation,  mention  of 13 

Copper,  engraving  on 89, 90 

etching  in  relief  on,  process  and  advan- 
tages of 75 

Copying,  methods  of 46^8 

C-orrections.    See  Changes. 

Cost  of  photo-engravings 75,78,80,81 

County  maps,  use  of 15 

Crayons,  wax,  use  of. 26,50,51 

Credit  for  data  of  maps,  indication  of 13 

Crystals,  drawings  of,  making  and  lettering  of.       70 


Page. 

Cultin-al  featmes,  lettering  of 53, 54 

list  of. 52-53 

Curves,  plate  showing 64 

Cuts.    See  Engravings. 

D. 

Details  of  a  geologic  map,  plate  showing 68 

Diagrams,  drawing  and  lettering  of 64 

features  of,  plate  showing 64 

original,  general  requirements  for 28-29 

Director  of  the  Survey ,  order  by 9 

Divisions  of  plates  and  figures,  serial  letters 

and  numbers  for 12 

Drafting  table,  shadowless,  description  of 47-48 

shadowless,  use  of 29, 48, 60 

Draftsmen,  detail  of,  to  aid  author 9 

detail  of,  to  prepare  base  maps 13-14 

experience  and  reading  required  by 41-42 

general  treatment  of  material  by 42-43 

Drainage  features,  depiction  of. 51-52 

Drawing  instruments,  list  of 42 

Drawing  materials,  kinds  used. . .  23-26, 66-67, 69, 71 
Drawings,  authors',  draftsmen  may  aid  in 

making 9 

authors',  editorial  revision  of 38 

finished,  general  requirements  for 41-42 

requests  for  photographs  of 34 

Duplicates  of  engravings,  charges  for 38 

E. 
Effectiveness  of  illustrations,  elements  that 

produce 7,39 

Electrotypes  of  engravings,  charges  for 38 

Elements,  chemical,  names  and  symbols  of. .       93 

Engraving  on  stone,  process  of. 89-90 

See  also  Lithography. 

Engravings,  changes  in 38-39 

original,  time  of  keeping 37 

Erasers,  injiu-y  to  paper  by 67 

kinds  used 25,67-68 

Erasures,  smoothing  paper  after 68 

Explanations  on  maps,  arrangement  and  let- 
tering of 19, 58-59 

F. 

Figures,  differences  from  plates 10-11 

divisions  of,  serial  letters  for 12 

methods  of  insert  ing,  plate  showing 12 

Formations,  geologic,  use  of  letter  symbols  for  20-21 

Fossils.    See  Specimens. 

Four-color  process,  advantage  of 80 

G. 

Gas  wells,  symbols  for 21 

General  ization,  true,  meaning  of 17 

Geographic  tables  and  formulas  (Buii.  650), 

use  of 44, 45 

Geologic  periods  of  time,  names  of 92 

Gouache,  use  of 67, 69 

Great  Lakes  surveys,  maps  published  by 15 

99 


100 


INDEX. 


Page. 
Greek  letters,  forms,  names,  and  English 

sounds  of 93 

Ground-water  features,  symbols  representing.  21-23 

H. 

Hachuring,  use  of 50 

Half-tone  engraving,  preparation  of  copy  for.  77-78 

process  and  advantages  of 75-78 

three-color  process  of 78-80 

Half  tones,  changes  in 39 

prints  of,  showing  effects  produced  by 

different  screens 56 

requirements  for  printing 11 

Heliotype.    See  Photogelatin  processes. 

Hill  shading,  use  of 50-51 

Hydrographic  features,  lettering  of 54 

representation  of 51-52 

Hypsographic  features,  lettering  of 54 

I. 

Illustrations,  kinds  of 10-11 

Inks,  kinds  used 25, 67 

methods  of  using 25 

Inserting  plates  and  figures,  methods  of,  plate 

showing 12 

Instruments,  draftsmen's,  list  of 42 

J. 

Japanese  transparent  water  colors,  use  of 26 

L. 

Land  Office  maps,  scales  and  detail  of 14-15 

Latitude,  length  of  1°  of,  at  intervals  of  10° 91 

Lending  of  photographs  and  drawings,  rules 

governing 34 

Letter  symbols,  use  of,  on  geologic  maps 20-21 

Lettering,  directions  for 53-55 

for  lithographing 90 

for  names  of  streams 52, 54 

on  diagrams 64 

on  drawings  of  crystals 70 

on  original  maps 19 

on  plans  and  cross  sections  of  mines 65-66 

reduction  sheet  used  in,  plate  showing. . .       54 

use  of  type  for 54-55 

Light,  direction  and  gradation  of 06 

Lithographs,  printing  and  insertion  of 11 

Lithography,  original  process  of 83-85 

See  also  Engraving  on  stone. 
Longitude,  length  of  1°  of,  at  latitudesO"  to90°.       91 

M. 

Map  of  the  world,  millionth-scale,  use  of,  for 

base  maps 14 

Maps,  arcal  patterns  for,  drawing  of 61-62 

bar  scales  for 59-60 

base,  conventional  symbols  used  on 45-46 

including  new  data,  how  obtained. . .  13-14 

indication  of  som-ces  on 13 

of  the  United  States  on  small  scales, 

use  of 15 

published  maps  available  for 14-17 

reuse  of,  to  be  approved 13 

black  and  white,  patterns  used  on,  plate 

showing 62 

borders  for 57-58 

cnltural  foatiires  on 52-53 


Page. 

Maps,  enlargement  and  reduction  of 18 

explanations  for 19, 5*-59 

geologic,  details  of,  plate  showing 58 

printing  of 87-89 

standard  colors  for 62-63 

hydrographic  features  on 51-52 

lettering  on 53-55 

materials  used  for  dra'wing 23-26 

orientation  of 18 

original ,  margin  required  on 19 

original  base,  amount  of  detail  on 17 

must  be  free  from  colors  and  symbols .       28 

preparation  of 13-14, 17-18 

original  geologic,  method  of  coloring 27-28 

projection  for 18-19,43-45 

reduction  or  enlargment  of,  marking  for..  63-64 

reUef  on 48-51 

standard  scales  for 18 

symbols  used  on 20-23 

drawing  of ^ 61 

plates  showing 20, 46 

titles  for 58 

topographic,  scales  of 14-15 

Mathematical  signs,  forms  and  names  of 94 

Measures,  linear,  metric  equivalents  of 92 

Measuring  scales  for  map  projection,  use  of...       44 
Meridians   used  on   public-land  maps,   dia- 
gram showing 16 

Metric  measures,  English  equivalents  of 92 

MUlionth-scale  map,  use  of 14 

Mine  plans,  conventional  lines  for 29 

fcatiu-cs  of 65-^ 

symbols  used  on,  plate  showing 20 

Minerals.    See  Rocks. 

Mississippi  River  Commission,  maps  pub- 
lished by U 

N. 

Names  of  rocks 94-97 

National  forest  maps  and  proclamations,  use 

of 15 

O. 

Offset  process,  description  of 87 

Oil  wells,  s>Tnbols  for 21 

Opaquing,  meaning  of 18, 47, 86 

Orientation  of  maps,  requirements  for 18 

Original  drawings,  general  treatment  of,  by 

draftsmen 42-43 

preparation  of 12-40 

Outdoor  sketches,  redrawing  of 69-70 

P. 

Panoramas,  construction  of 71 

Paper,  kinds  used  for  drawings. .  23-24,50,51,66,69 

Pastes,  use  of 37 

Patterns,  areal,  method  of  drawing 61-62 

aroal,  plate  showing 62 

Pen  dramngs,  materials  and  methods  used 

in  making 67-68,68-69 

Pencils,  colored,  use  of 26 

drawing,  quality  and  grades  of 25,66 

Pens,  kinds  of,  used  for  drawing 25, 48, 67 

Photo-engraving,  cost  of 75, 78, 80, 81 

general  features  of 72-73 

Photo-engravings,  printing  and  insertion  of.       11 
Photo-gelatin  processes,  desciiption  of 82-83 


INDEX. 


101 


Photographs,  adaptation  of. 33 

bleaching  of 69 

care  needed  in  taking  and  handling.  32, 33, 39-40 

copyrighted,  consent  for  use  of 33-34 

duplicate  prints  of,  requests  for 34 

mounting  and  numbering  of 33, 36-37 

poor,  making  of  drawings  over 68-69 

preparation  of,  for  half-tone  engraving. . .  77-78 

record  of  source  of 34 

selection  of 32-33 

retouching  of 68, 70-71 

suitabiUty  of 9 

unpublished,  issue  and  use  of 34 

Photolithogi'aphs,  changes  in 39 

Photolithography,  description  of 86-S7 

Planographic  process,  description  of 87 

Plans  of  mines,  drawing  and  lettering  of. .  29, 65-66 

symbols  used  on,  plate  showing 20 

Plates,  differences  from  figures 10-11 

divisions  of,  serial  letters  and  numbers  for.       12 

grouping  small  illustrations  on 36-37 

methods  of  inserting,  plate  showing 12 

Political  divisions,  lettering  of 53, 54 

Post-route  maps,  scales  and  detail  of 15 

Projection  for  maps,  preparation  and  check- 
ing of 18-19,43-45 

Proofs,  changes  in 75 

correction  of 38-39 

duplicate,  supplying  of 39 

submittal  of 38 

Public-land  max)s,  meridians,  parallels,  and 
township  lines  used  on,  diagram 

showing 16 

Public  works,  lettering  of 63 

Punctuation  marks,  forms  of 54 

Purpose  of  illustrations  in  Survey  reports 8,40 

R. 
Railroad  surveys,  data  for  maps  obtainable 

from 16 

Railroads,  names  of,  on  maps 57 

Reduction  of  maps,  marking  drawings  for . . .  63-64 

means  of IS 

Reduction  sheet  for  lettering,  plate  showing.       54 

use  of 55 

Relief,  methods  o  f  expressing 48-51 

Reproduction  of  illustpations,  processes  for. .  72-90 

relation  of,  to  the  drawing  supplied 7, 40 

Reticulation,  sketching  by 47 

Retouching  of  photographs,  materials  and 

method  used  in 68, 70-71 

Reuse  of  illustrations,  procedure  for 37-38 

Rocks,  igneous,  names  of 95-OT 

metamorphic,  names  of 95 

sedimentary,  names  of 94r-95 

symbols  used  to  distinguish 32 

See  also  Specimens. 

Roman  numerals,  numbers  expressed  by 93 

Rubber,  liquid,  use  of 37 

S. 

Scales,  bar,  forms  of 59-60 

measuring  for  projection  of  maps 44 

standard,  of  maps 18 

Scope  of  this  manual 7 

Screens,  half-tone  prints  showing  effects  pro- 
duced by 56 

Selection  of  illustrations,  considerations  gov- 
erning   8-9 


Page. 

Sections,  columnar,  original  drawings  for 31 

columnar,  symbols  used  in,  plate  showing       32 
structure,  combination  of,  with  views  of 

topography 30-31 

drawing  of 64-65 

original  drawings  for 29-31 

symbols  used  in,  plate  showing 32 

vertical  exaggeration  of 30 

Shading,  kinds  used 67 

Signs,  mathematical,  forms  and  names  of 94 

Sizes  o  f  illustrations 11-12, 40 

Specimens,  borrowed  and  fragile,  care  of 35 

drawings  of,  methods  ofmaking 66-68 

paleontologic,  transmittal  of 35 

photographs  of,  how  printed 68 

how  used 34-35 

Springs,  symbols  for 22, 23 

State  maps,  use  of 15 

Stipple,  production  of 50, 51 

Stone,  engraving  on 89-90 

Streams,  drawing  of 51-52 

lettering  names  of 52 

Submittal  of  illustrations 10 

Sym.bols,  drawing  of 20, 61 

for   ground-water   features,    imiformity 

needed  in 21-23 

for  maps  and  mine  plans,  plates  showing.  20, 46 

uniform  use  of 20, 45-46 

for  oil  and  gas  wells,  features  of 21 

for  structiue  and  columnar  sections,  plate 

showing 32 

lithologic,  use  of 32 

T. 

Three-colorhalf-tones,  process  of  making 78-80 

Titles  of  illustrations,  arrangement  and  place 

of 58 

printing  of 19-20 

wording  and  lettering  of 19 

Tooling  on  half-tones,  efiects  obtained  by 77, 78 

Topographic  atlas  sheets,  scales  of 14 

Tracing,  method  of 46-47 

use  of  colors  in 46-47 

Tracing  linen,  use  of 24-25 

Transferring,  celluloid,  process  of 47 

celluloid,  requisitions  for 47 

Type,  lettering  with 54-55 

styles  and  sizes  of 55 

V. 

Value  o  f  illustrations  in  Survey  reports 8 

Vara,  length  of 92 

Vignetting,  effect  obtained  by 78 

W. 

Wall  map  of  the  United  States,  use  of,  for 

base  maps 14 

Watercolors,  useof 26,67,71 

Waterhning,  use  of 62 

Wax  engraving,  process  and  advantages  of.. .  80-81 

Wells,  symbols  for 22, 23 

Wood  engraving,  processof 81-82 

Z. 

Zinc  etchings,  changes  in 38-39 

drawings  for 74 

insertion  of n 

making  and  advantages  of 73-75 


o 


GETTY  CENTER  LIBRARY 


3  3125  00019  0393 


